diff --git a/new/AutoItInterpreter/AssemblyInfo.cs b/new/AutoItInterpreter/AssemblyInfo.cs
index bddc8f55..b7679ac7 100644
--- a/new/AutoItInterpreter/AssemblyInfo.cs
+++ b/new/AutoItInterpreter/AssemblyInfo.cs
@@ -1,15 +1,15 @@
 
 //////////////////////////////////////////////////////////////////////////
-// Auto-generated 2020-07-26 17:04:48.009                               //
+// Auto-generated 2020-07-27 01:57:30.012                               //
 // ANY CHANGES TO THIS DOCUMENT WILL BE LOST UPON RE-GENERATION         //
 //////////////////////////////////////////////////////////////////////////
 
 using System.Reflection;
 using System;
 
-[assembly: AssemblyVersion("0.6.1256.7328")]
-[assembly: AssemblyFileVersion("0.6.1256.7328")]
-[assembly: AssemblyInformationalVersion("cdfd24e8c9341f9fc41540bef89d37e540605174")]
+[assembly: AssemblyVersion("0.6.1257.7329")]
+[assembly: AssemblyFileVersion("0.6.1257.7329")]
+[assembly: AssemblyInformationalVersion("f3c8f7753e53011c5fac5224b49c3724c68f2759")]
 [assembly: AssemblyCompany("Unknown6656")]
 [assembly: AssemblyCopyright("Copyright © 2018 - 2020, Unknown6656")]
 [assembly: AssemblyProduct("AutoIt3 Interpreter by Unknown6656")]
@@ -35,11 +35,11 @@ public static class __module__
     /// <summary>
     /// The interpreter's current version.
     /// </summary>
-    public static Version? InterpreterVersion { get; } = Version.Parse("0.6.1256.7328");
+    public static Version? InterpreterVersion { get; } = Version.Parse("0.6.1257.7329");
     /// <summary>
     /// The Git hash associated with the current build.
     /// </summary>
-    public const string GitHash = "cdfd24e8c9341f9fc41540bef89d37e540605174";
+    public const string GitHash = "f3c8f7753e53011c5fac5224b49c3724c68f2759";
     /// <summary>
     /// The URL of this project's Git(Hub) repository.
     /// </summary>
diff --git a/new/AutoItInterpreter/MainProgram.cs b/new/AutoItInterpreter/MainProgram.cs
index a5d7b072..6819b100 100644
--- a/new/AutoItInterpreter/MainProgram.cs
+++ b/new/AutoItInterpreter/MainProgram.cs
@@ -135,7 +135,7 @@ public static int Start(string[] argv)
 
             Console.CancelKeyPress += (_, e) =>
             {
-                Interpreter[] instances = Interpreter.Instances;
+                Interpreter[] instances = Interpreter.ActiveInstances;
 
                 e.Cancel = instances.Length > 0;
 
diff --git a/new/AutoItInterpreter/Runtime/AU3Thread.cs b/new/AutoItInterpreter/Runtime/AU3Thread.cs
index 1a67c6bd..d09a1145 100644
--- a/new/AutoItInterpreter/Runtime/AU3Thread.cs
+++ b/new/AutoItInterpreter/Runtime/AU3Thread.cs
@@ -1,24 +1,14 @@
-using System.Text.RegularExpressions;
-using System.Collections.Concurrent;
-using System.Collections.Generic;
+using System.Collections.Concurrent;
 using System.Linq;
 using System;
 
-using Microsoft.FSharp.Collections;
-using Microsoft.FSharp.Core;
-
-using Piglet.Parser.Configuration.Generic;
-
-using Unknown6656.AutoIt3.Extensibility.Plugins.Au3Framework;
-using Unknown6656.AutoIt3.Extensibility.Plugins.Internals;
-using Unknown6656.AutoIt3.ExpressionParser;
-using Unknown6656.AutoIt3.Extensibility;
 using Unknown6656.Common;
 
-using static Unknown6656.AutoIt3.ExpressionParser.AST;
-
 namespace Unknown6656.AutoIt3.Runtime
 {
+    /// <summary>
+    /// Represents an AutoIt execution thread. The thread consists of multiple call frames which in term represent function invocations.
+    /// </summary>
     public sealed class AU3Thread
         : IDisposable
         , IEquatable<AU3Thread>
@@ -29,24 +19,51 @@ public sealed class AU3Thread
         private int? _override_exitcode = null;
 
 
+        /// <summary>
+        /// The <see cref="Runtime.Interpreter"/> on which the current thread has been created.
+        /// </summary>
         public Interpreter Interpreter { get; }
 
+        /// <summary>
+        /// Indicates whether the current thread is actively running.
+        /// </summary>
         public bool IsRunning => _running;
 
+        /// <summary>
+        /// The top-most <see cref="CallFrame"/>, representing the top-most function invocation of this thread.
+        /// </summary>
         public CallFrame? CurrentFrame => _callstack.TryPeek(out CallFrame? lp) ? lp : null;
 
+        /// <summary>
+        /// The <see cref="SourceLocation"/> of the currently executed statement or line.
+        /// </summary>
         public SourceLocation? CurrentLocation => CallStack.OfType<AU3CallFrame>().FirstOrDefault()?.CurrentLocation ?? SourceLocation.Unknown;
 
+        /// <summary>
+        /// The currently executed function.
+        /// </summary>
         public ScriptFunction? CurrentFunction => CurrentFrame?.CurrentFunction;
 
         public VariableScope CurrentVariableResolver => CurrentFrame?.VariableResolver ?? Interpreter.VariableResolver;
 
+        /// <summary>
+        /// The current call stack (function invocation stack) of this thread. The first item of the collection represents the top-most thread and holds the same value as <see cref="CurrentFrame"/>.
+        /// </summary>
         public CallFrame[] CallStack => CurrentFrame.Propagate(frame => (frame?.CallerFrame, frame is { })).ToArrayWhere(frame => frame is { })!;
 
+        /// <summary>
+        /// Indicates whether the current thread has been disposed.
+        /// </summary>
         public bool IsDisposed { get; private set; }
 
+        /// <summary>
+        /// Indicates whether the current thread is the <see cref="Interpreter.MainThread"/> of the associated <see cref="Runtime.Interpreter"/>.
+        /// </summary>
         public bool IsMainThread => ReferenceEquals(this, Interpreter.MainThread);
 
+        /// <summary>
+        /// The unique ID of this thread.
+        /// </summary>
         public int ThreadID { get; }
 
 
@@ -59,6 +76,14 @@ internal AU3Thread(Interpreter interpreter)
             MainProgram.PrintfDebugMessage("debug.au3thread.created", this);
         }
 
+        /// <summary>
+        /// Starts the current thread by invoking the given <paramref name="ScriptFunction"/> with the given arguments.
+        /// <para/>
+        /// This function is blocking and returns only after the given function has been invoked.
+        /// </summary>
+        /// <param name="function">The function to be invoked.</param>
+        /// <param name="args">The arguments to be passed to the function.</param>
+        /// <returns>The functions return value or execution error.</returns>
         public Union<InterpreterError, Variant> Start(ScriptFunction function, Variant[] args) =>
             Interpreter.Telemetry.Measure<Union<InterpreterError, Variant>>(TelemetryCategory.ThreadRun, delegate
             {
@@ -77,6 +102,16 @@ public Union<InterpreterError, Variant> Start(ScriptFunction function, Variant[]
                 return result;
             });
 
+        /// <summary>
+        /// <b>[UNSAFE!]</b>
+        /// Invokes the given <paramref name="ScriptFunction"/> with the given arguments. A call to this function is considered to be unsafe, as any non-concurrent call may result into undefined behavior.
+        /// Use <see cref="Start"/> instead.
+        /// <para/>
+        /// This function is blocking and returns only after the given function has been invoked.
+        /// </summary>
+        /// <param name="function">The function to be invoked.</param>
+        /// <param name="args">The arguments to be passed to the function.</param>
+        /// <returns>The functions return value or execution error.</returns>
         public Union<InterpreterError, Variant> Call(ScriptFunction function, Variant[] args)
         {
             if (IsDisposed)
@@ -100,6 +135,9 @@ public Union<InterpreterError, Variant> Call(ScriptFunction function, Variant[]
             return result;
         }
 
+        /// <summary>
+        /// Stops the current thread execution. This will dispose the current thread.
+        /// </summary>
         public void Stop()
         {
             _running = false;
@@ -107,6 +145,10 @@ public void Stop()
             Dispose();
         }
 
+        /// <summary>
+        /// Stops the current thread execution with the given exit code. This will dispose the current thread.
+        /// </summary>
+        /// <param name="exitcode">Exit code, with which the current thread will return.</param>
         public void Stop(int exitcode)
         {
             Stop();
@@ -126,14 +168,19 @@ public void Stop(int exitcode)
             return CurrentLocation;
         }
 
+        /// <inheritdoc/>
         public override string ToString() => $"0x{ThreadID:x4}{(IsMainThread ? " (main)" : "")} @ {CurrentLocation}";
 
+        /// <inheritdoc/>
         public override int GetHashCode() => HashCode.Combine(Interpreter, ThreadID);
 
+        /// <inheritdoc/>
         public override bool Equals(object? obj) => obj is AU3Thread thread && Equals(thread);
 
+        /// <inheritdoc/>
         public bool Equals(AU3Thread? other) => Interpreter == other?.Interpreter && ThreadID == other?.ThreadID;
 
+        /// <inheritdoc/>
         public void Dispose()
         {
             _running = false;
@@ -151,1562 +198,4 @@ public void Dispose()
             MainProgram.PrintfDebugMessage("debug.au3thread.disposed", this);
         }
     }
-
-#pragma warning disable CA1063
-    // TODO : covariant return for 'CurrentFunction'
-    public abstract class CallFrame
-        : IDisposable
-    {
-        public AU3Thread CurrentThread { get; }
-
-        public virtual ScriptFunction CurrentFunction { get; }
-
-        public VariableScope VariableResolver { get; }
-
-        public Variant[] PassedArguments { get; }
-
-        public CallFrame? CallerFrame { get; }
-
-        public Variant ReturnValue { protected set; get; } = Variant.Zero;
-
-        public virtual SourceLocation CurrentLocation => CurrentThread.CurrentLocation ?? CurrentFunction.Location;
-
-        public Interpreter Interpreter => CurrentThread.Interpreter;
-
-
-        internal CallFrame(AU3Thread thread, CallFrame? caller, ScriptFunction function, Variant[] args)
-        {
-            CurrentThread = thread;
-            CallerFrame = caller;
-            CurrentFunction = function;
-            PassedArguments = args;
-
-            // TODO : the following line is wrong - it should be interpreter as parent, not the previous frame
-            VariableResolver = function.IsMainFunction ? thread.CurrentVariableResolver : thread.CurrentVariableResolver.CreateChildScope(this);
-        }
-
-        public void Dispose() => VariableResolver.Dispose();
-
-        protected abstract Union<InterpreterError, Variant> InternalExec(Variant[] args);
-
-        internal Union<InterpreterError, Variant> Execute(Variant[] args)
-        {
-            Union<InterpreterError, Variant> result = Variant.Zero;
-            ScannedScript script = CurrentFunction.Script;
-
-            SetError(0, 0);
-
-            Interpreter.Telemetry.Measure(TelemetryCategory.OnAutoItStart, delegate
-            {
-                if (CurrentFunction.IsMainFunction && script.LoadScript(this) is InterpreterError load_error)
-                    result = load_error;
-            });
-
-            (int min_argc, int max_argc) = CurrentFunction.ParameterCount;
-
-            if (args.Length < min_argc)
-                return InterpreterError.WellKnown(CurrentThread.CurrentLocation, "error.not_enough_args", CurrentFunction.Name, min_argc, args.Length);
-            else if (args.Length > max_argc)
-                return InterpreterError.WellKnown(CurrentThread.CurrentLocation, "error.too_many_args", CurrentFunction.Name, max_argc, args.Length);
-            else if (result.Is<Variant>())
-                if (CurrentThread.IsRunning)
-                {
-                    MainProgram.PrintfDebugMessage("debug.au3thread.executing", CurrentFunction);
-
-                    result = Interpreter.Telemetry.Measure(TelemetryCategory.ScriptExecution, () => InternalExec(args));
-                }
-
-            Interpreter.Telemetry.Measure(TelemetryCategory.OnAutoItExit, delegate
-            {
-                if (CurrentFunction.IsMainFunction && result.Is<Variant>() && script.UnLoadScript(this) is InterpreterError unload_error)
-                    result = unload_error;
-            });
-
-            if (result.Is(out Variant @return))
-                ReturnValue = @return;
-
-            return result;
-        }
-
-        public Union<InterpreterError, Variant> Call(ScriptFunction function, Variant[] args) => CurrentThread.Call(function, args);
-
-        public Variant SetError(int error, Variant? extended = null, in Variant @return = default)
-        {
-            Interpreter.ErrorCode = error;
-
-            return SetExtended(extended, in @return);
-        }
-
-        public Variant SetExtended(Variant? extended, in Variant @return = default)
-        {
-            Interpreter.ExtendedValue = extended ?? Variant.Null;
-
-            return @return;
-        }
-
-        public void Print(Variant value) => Interpreter.Print(this, value);
-
-        public void Print(object? value) => Interpreter.Print(this, value);
-
-        public override string ToString() => $"[0x{CurrentThread.ThreadID:x4}]";
-
-        internal void IssueWarning(string key, params object?[] args) => MainProgram.PrintWarning(CurrentLocation, Interpreter.CurrentUILanguage[key, args]);
-    }
-#pragma warning restore CA1063
-
-    public sealed class NativeCallFrame
-        : CallFrame
-    {
-        internal NativeCallFrame(AU3Thread thread, CallFrame? caller, NativeFunction function, Variant[] args)
-            : base(thread, caller, function, args)
-        {
-        }
-
-        protected override Union<InterpreterError, Variant> InternalExec(Variant[] args)
-        {
-            FunctionReturnValue result = Interpreter.Telemetry.Measure(TelemetryCategory.NativeScriptExecution, () => ((NativeFunction)CurrentFunction).Execute(this, args));
-            Variant? extended = null;
-            int error = 0;
-
-            if (result.IsFatal(out InterpreterError? fatal))
-                return fatal;
-            else if (result.IsSuccess(out Variant variant, out extended) || result.IsError(out variant, out error, out extended))
-                return SetError(error, extended, in variant);
-            else
-                throw new InvalidOperationException("Return value could not be processed");
-        }
-
-        public override string ToString() => $"{base.ToString()} native call frame";
-    }
-
-    public sealed class AU3CallFrame
-        : CallFrame
-    {
-        private const RegexOptions _REGEX_OPTIONS = RegexOptions.IgnoreCase | RegexOptions.Compiled;
-        private static readonly Regex REGEX_INTERNAL_LABEL = new Regex(@"^§\w+$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_VARIABLE = new Regex(@"\$([^\W\d]|[^\W\d]\w*)\b", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_GOTO = new Regex(@"^goto\s+(?<label>.+)$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_WHILE = new Regex(@"^while\s+(?<expression>.+)$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_WEND = new Regex(@"^wend$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_NEXT = new Regex(@"^next$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_EXIT = new Regex(@"^exit(\b\s*(?<code>.+))?$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_RETURN = new Regex(@"^return(\b\s*(?<value>.+))?$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_FOR = new Regex(@"^for\s+.+$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_FORTO = new Regex(@"^for\s+(?<start>.+)\s+to\s+(?<stop>.+?)(\s+step\s+(?<step>.+))?$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_FORIN = new Regex(@"^for\s+(?<variable>.+)\s+in\s+(?<expression>.+)$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_FORIN_VARIABLES = new Regex(@"^\$(?<key>[^\W\d]|[^\W\d]\w*)\s*,\s*\$(?<value>[^\W\d]|[^\W\d]\w*)$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_WITH = new Regex(@"^with\s+(?<variable>.+)$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_ENDWITH = new Regex(@"^endwith$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_REDIM = new Regex(@"^redim\s+(?<expression>.+)$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_DO = new Regex(@"^do$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_UNTIL = new Regex(@"^until\s+(?<expression>.+)$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_IF = new Regex(@"^(?<elif>else)?if\s+(?<condition>.+)\s+then$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_ELSE = new Regex(@"^else$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_ENDIF = new Regex(@"^endif$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_DECLARATION_MODIFIER = new Regex(@"^(local|static|global|const|dim|enum|step)\b", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_ENUM_STEP = new Regex(@"^(?<op>[+\-*]?)(?<step>\d+)\b", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_INCLUDE = new Regex(@"^include?\s+(?<open>[""'<])(?<path>(?:(?!\k<close>).)+)(?<close>[""'>])$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_CONTINUELOOP_EXITLOOP = new Regex(@"^(?<mode>continue|exit)loop\s*(?<level>.+)?\s*$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_SELECT = new Regex(@"^select$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_ENDSELECT = new Regex(@"^endselect$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_SWITCH = new Regex(@"^switch\b\s*(?<expression>.+)$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_ENDSWITCH = new Regex(@"^endswitch$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_CASE = new Regex(@"^case\b\s*(?<expression>.+)*$", _REGEX_OPTIONS);
-        private static readonly Regex REGEX_CONTINUECASE = new Regex(@"^continuecase$", _REGEX_OPTIONS);
-
-        private readonly ConcurrentDictionary<string, IEnumerator<(Variant key, Variant value)>> _iterators = new();
-        private readonly ConcurrentStack<Variable> _withcontext_stack = new ConcurrentStack<Variable>();
-        private readonly ConcurrentStack<bool> _if_stack = new ConcurrentStack<bool>();
-        private readonly ConcurrentStack<string> _while_stack = new();
-        private readonly ConcurrentStack<(Variant? switch_expression, bool case_handled)> _switchselect_stack = new();
-
-        private volatile int _instruction_pointer = 0;
-        private List<(SourceLocation LineLocation, string LineContent)> _line_cache;
-
-
-        public int CurrentInstructionPointer => _instruction_pointer;
-
-        public (SourceLocation LineLocation, string LineContent)[] CurrentLineCache => _line_cache.ToArray();
-
-        public override SourceLocation CurrentLocation => _instruction_pointer < 0 ? CurrentFunction.Location : _line_cache[_instruction_pointer].LineLocation;
-
-        public string CurrentLineContent => _instruction_pointer < 0 ? '<' + Interpreter.CurrentUILanguage["general.unknown"] + '>' : _line_cache[_instruction_pointer].LineContent;
-
-        public Dictionary<string, int> InternalJumpLabels => _line_cache.WithIndex().Where(l => REGEX_INTERNAL_LABEL.IsMatch(l.Item.LineContent)).ToDictionary(l => l.Item.LineContent, l => l.Index);
-
-
-        internal AU3CallFrame(AU3Thread thread, CallFrame? caller, AU3Function function, Variant[] args)
-            : base(thread, caller, function, args)
-        {
-            _line_cache = function.Lines.ToList();
-            _instruction_pointer = 0;
-        }
-
-        public override string ToString() => $"{base.ToString()} {CurrentLocation}";
-
-        protected override Union<InterpreterError, Variant> InternalExec(Variant[] args)
-        {
-            _instruction_pointer = -1;
-
-            AU3Function func = (AU3Function)CurrentFunction;
-            int argc = func.ParameterCount.MaximumCount;
-            int len = args.Length;
-
-            if (len < argc)
-                Array.Resize(ref args, argc);
-
-            for (int i = 0; i < argc; ++i)
-            {
-                PARAMETER_DECLARATION param = func.Parameters[i];
-                Variable param_var = VariableResolver.CreateVariable(func.Location, param.Variable.Name, param.IsConst);
-
-                if (i < len)
-                {
-                    if (param.IsByRef && args[i].AssignedTo is Variable existing)
-                        if (existing.IsConst)
-                            return WellKnownError("error.constant_passed_as_ref", existing, i + 1);
-                        else
-                            args[i] = Variant.FromReference(existing);
-                }
-                else if (param.DefaultValue is null)
-                    return WellKnownError("error.missing_argument", i + 1, param.Variable);
-                else
-                {
-                    EXPRESSION expr = param.DefaultValue.Value;
-                    Union<InterpreterError, Variant> result = ProcessExpression(expr);
-
-                    if (result.Is(out InterpreterError? error))
-                        return error;
-                    else if (result.Is(out Variant value))
-                        args[i] = value;
-                }
-
-                param_var.Value = args[i];
-            }
-
-            return Interpreter.Telemetry.Measure<Union<InterpreterError, Variant>>(TelemetryCategory.Au3ScriptExecution, delegate
-            {
-                _instruction_pointer = 0;
-
-                while (_instruction_pointer < _line_cache.Count && CurrentThread.IsRunning)
-                    if (ParseCurrentLine()?.OptionalError is InterpreterError error)
-                        return error;
-                    else if (!MoveNext())
-                        break;
-
-                return ReturnValue;
-            });
-        }
-
-        private bool MoveNext()
-        {
-            if (_instruction_pointer < _line_cache.Count)
-            {
-                ++_instruction_pointer;
-
-                return true;
-            }
-            else
-                return false;
-        }
-
-        private bool MoveAfter(SourceLocation closest_location)
-        {
-            _instruction_pointer = (from ln in _line_cache.WithIndex()
-                                    let loc = ln.Item.LineLocation
-                                    where loc >= closest_location
-                                    orderby loc ascending
-                                    select ln.Index).FirstOrDefault();
-
-            return _instruction_pointer < _line_cache.Count;
-        }
-
-        private bool MoveBefore(SourceLocation closest_location)
-        {
-            MoveAfter(closest_location);
-            --_instruction_pointer;
-
-            return _instruction_pointer < _line_cache.Count;
-        }
-
-        private bool MoveTo(JumpLabel jump_label) => MoveAfter(jump_label.Location);
-
-        private InterpreterError? MoveTo(string jump_label)
-        {
-            if (InternalJumpLabels.TryGetValue(jump_label, out int index))
-            {
-                _instruction_pointer = index;
-
-                return null;
-            }
-            else if ((CurrentFunction as AU3Function)?.JumpLabels[jump_label] is JumpLabel label)
-            {
-                MoveTo(label);
-
-                return null;
-            }
-
-            return WellKnownError("error.unknown_jumplabel", jump_label);
-        }
-
-        /// <summary>
-        /// Copies the given value into the <see cref="CallFrame.ReturnValue"/>-field, and moves the instruction pointer to the end.
-        /// </summary>
-        /// <param name="value">Return value</param>
-        public void Return(Variant value)
-        {
-            _instruction_pointer = _line_cache.Count;
-            ReturnValue = value;
-        }
-
-        private bool RemoveInternalJumpLabel(string jump_label)
-        {
-            if (REGEX_INTERNAL_LABEL.IsMatch(jump_label))
-                for (int i = 0; i < _line_cache.Count; i++)
-                    if (jump_label.Equals(_line_cache[i].LineContent))
-                    {
-                        _line_cache.RemoveAt(i);
-
-                        return true;
-                    }
-
-            return false;
-        }
-
-        private string InsertInternalJumpLabel()
-        {
-            string name = $"§{Guid.NewGuid():N}";
-
-            if (_instruction_pointer < _line_cache.Count)
-                _line_cache.Insert(_instruction_pointer, (CurrentLocation, name));
-            else
-                _line_cache.Add((SourceLocation.Unknown, name));
-
-            ++_instruction_pointer;
-
-            return name;
-        }
-        
-        private void InsertReplaceSourceCode(int instruction_ptr, params string[] lines)
-        {
-            int eip = _instruction_pointer;
-
-            _instruction_pointer = instruction_ptr;
-
-            if (lines.Length == 1)
-            {
-                if (_instruction_pointer < _line_cache.Count)
-                    _line_cache[_instruction_pointer] = (CurrentLocation, lines[0]);
-                else
-                    _line_cache.Add((SourceLocation.Unknown, lines[0]));
-            }
-            else
-            {
-                _line_cache.RemoveAt(_instruction_pointer);
-
-                if (_instruction_pointer < _line_cache.Count)
-                    _line_cache.InsertRange(_instruction_pointer, lines.Select(l => (CurrentLocation, l)));
-                else
-                    _line_cache.AddRange(lines.Select(l => (SourceLocation.Unknown, l)));
-            }
-
-            _instruction_pointer = eip;
-        }
-
-        public InterpreterResult? ParseCurrentLine()
-        {
-            (SourceLocation loc, string line) = _line_cache[_instruction_pointer];
-            InterpreterResult? result = null;
-
-            line = line.Trim();
-
-            MainProgram.PrintDebugMessage("-----------------------------------------------------------------------------------------------");
-            MainProgram.PrintfDebugMessage("debug.au3thread.location", loc);
-            MainProgram.PrintfDebugMessage("debug.au3thread.content", line);
-
-            if (string.IsNullOrEmpty(line) || REGEX_INTERNAL_LABEL.IsMatch(line))
-                return InterpreterResult.OK;
-
-            Interpreter.Telemetry.Measure(TelemetryCategory.ProcessLine, delegate
-            {
-                result ??= ProcessDirective(line);
-                result ??= ProcessStatement(line);
-                result ??= UseExternalLineProcessors(line);
-                result ??= ProcessExpressionStatement(line);
-            });
-
-            if (Interpreter.CommandLineOptions.IgnoreErrors && result?.OptionalError?.Message is string msg)
-            {
-                MainProgram.PrintWarning(CurrentLocation, msg);
-
-                result = null;
-            }
-
-            return result ?? InterpreterResult.OK;
-        }
-
-        private InterpreterResult? ProcessDirective(string directive)
-        {
-            if (!directive.StartsWith('#'))
-                return null;
-
-            directive = directive[1..];
-
-            InterpreterResult? result = Interpreter.Telemetry.Measure(TelemetryCategory.ProcessDirective, delegate
-            {
-                if (directive.Match(REGEX_INCLUDE, out ReadOnlyIndexer<string, string>? g))
-                {
-                    char open = g["open"][0];
-                    char close = g["close"][0];
-                    bool relative = open != '<';
-
-                    if (open != close && open != '<' && close != '>')
-                        return WellKnownError("error.mismatched_quotes", open, close);
-
-                    return Interpreter.ScriptScanner.ScanScriptFile(CurrentLocation, g["path"], relative).Match(err => err, script =>
-                    {
-                        ScannedScript[] active = Interpreter.ScriptScanner.ActiveScripts;
-
-                        if (active.Contains(script))
-                        {
-                            if (script.IncludeOnlyOnce)
-                                return InterpreterResult.OK;
-                            else
-                                return WellKnownError("error.circular_include", script.Location.FullName);
-                        }
-                        else if (Call(script.MainFunction, Array.Empty<Variant>()).Is(out InterpreterError? err))
-                            return err;
-                        else
-                            return InterpreterResult.OK;
-                    });
-                }
-
-                return null;
-            });
-
-            foreach (AbstractDirectiveProcessor proc in Interpreter.PluginLoader.DirectiveProcessors)
-                result ??= Interpreter.Telemetry.Measure(TelemetryCategory.ProcessDirective, () => proc.ProcessDirective(this, directive));
-
-            if (result is null)
-                IssueWarning("warning.unparsable_dirctive", directive);
-
-            return InterpreterResult.OK;
-        }
-
-        private InterpreterError? MoveToEndOf(BlockStatementType type)
-        {
-            SourceLocation init = CurrentLocation;
-            int depth = 1;
-
-            if (type is BlockStatementType.If)
-                while (MoveNext())
-                {
-                    string line = CurrentLineContent.Trim();
-                    bool @if = false;
-
-                    if (line.Match(REGEX_IF, out Match m))
-                    {
-                        @if = true;
-
-                        if (m.Groups["elif"].Length > 0)
-                            --depth;
-                        else
-                            ++depth;
-                    }
-                    else if (REGEX_ELSE.IsMatch(line))
-                        --depth;
-                    else if (REGEX_ENDIF.IsMatch(line))
-                        --depth;
-
-                    if (depth == 0)
-                    {
-                        if (@if)
-                            --_instruction_pointer;
-
-                        break;
-                    }
-                }
-            else if (type is BlockStatementType.While or BlockStatementType.Select or BlockStatementType.Switch)
-            {
-                (Regex start, Regex end) = type switch
-                {
-                    BlockStatementType.Select => (REGEX_SELECT, REGEX_ENDSELECT),
-                    BlockStatementType.Switch => (REGEX_SWITCH, REGEX_ENDSWITCH),
-                    BlockStatementType.While => (REGEX_WHILE, REGEX_WEND),
-                    _ => throw new ArgumentOutOfRangeException(nameof(type)),
-                };
-
-                while (MoveNext())
-                {
-                    string line = CurrentLineContent.Trim();
-
-                    if (end.IsMatch(line))
-                        --depth;
-                    else if (type is not BlockStatementType.While && REGEX_CASE.IsMatch(line))
-                        --depth;
-                    else if (start.IsMatch(line))
-                        ++depth;
-
-                    if (depth == 0)
-                        break;
-                }
-            }
-
-            // TODO : other block types
-
-            else
-                return WellKnownError("error.not_yet_implemented", type);
-
-            return depth == 0 ? null : WellKnownError("error.no_matching_close", type, init);
-        }
-
-        private InterpreterResult? ProcessStatement(string line) => Interpreter.Telemetry.Measure(TelemetryCategory.ProcessStatement, delegate
-        {
-            InterpreterResult? result = line.Match(null, new Dictionary<Regex, Func<Match, InterpreterResult?>>
-            {
-                [REGEX_EXIT] = m =>
-                {
-                    string code = m.Groups["code"].Value;
-
-                    if (string.IsNullOrWhiteSpace(code))
-                        code = "0";
-
-                    Union<InterpreterError, Variant> result = ProcessAsVariant(code);
-
-                    if (result.Is(out Variant value))
-                    {
-                        Interpreter.Stop((int)value.ToNumber());
-
-                        return InterpreterResult.OK;
-                    }
-                    else
-                        return (InterpreterError)result;
-                },
-                [REGEX_RETURN] = m =>
-                {
-                    if (CurrentFunction.IsMainFunction)
-                        return WellKnownError("error.invalid_return");
-
-                    string optval = m.Groups["value"].Value;
-
-                    if (string.IsNullOrWhiteSpace(optval))
-                        optval = "0";
-
-                    Union<InterpreterError, Variant> result = ProcessAsVariant(optval);
-
-                    if (result.Is(out Variant value))
-                        Return(value);
-                    else
-                        return (InterpreterError)result;
-
-                    return InterpreterResult.OK;
-                },
-                [REGEX_FORTO] = m =>
-                {
-                    Union<InterpreterError, PARSABLE_EXPRESSION> start = ProcessAsRawExpression(m.Groups["start"].Value);
-                    string step = m.Groups["step"].Value is { Length: > 0 } s ? s : "1";
-
-                    if (start.Is(out InterpreterError? error))
-                        return error;
-                    else if (start.UnsafeItem is PARSABLE_EXPRESSION.AnyExpression
-                    {
-                        Item: EXPRESSION.Binary
-                        {
-                            Item:
-                            {
-                                Item1: EXPRESSION.Variable { Item: VARIABLE counter },
-                                Item2: { IsEqualCaseInsensitive: true },
-                            }
-                        }
-                    } assg)
-                    {
-                        if (ProcessAssignmentStatement(assg, false).Is(out error))
-                            return error;
-
-                        SourceLocation loc_for = CurrentLocation;
-                        int eip_for = _instruction_pointer;
-                        int depth = 1;
-
-                        while (MoveNext())
-                        {
-                            if (CurrentLineContent.Match(REGEX_NEXT, out Match _))
-                                --depth;
-                            else if (CurrentLineContent.Match(REGEX_FOR, out Match _))
-                                ++depth;
-
-                            if (depth == 0)
-                            {
-                                Variable v_first = VariableResolver.CreateTemporaryVariable();
-                                string first = '$' + v_first.Name;
-                                string stop = '$' + VariableResolver.CreateTemporaryVariable().Name;
-
-                                v_first.Value = Variant.True;
-
-                                InsertReplaceSourceCode(_instruction_pointer, $"WEnd");
-                                InsertReplaceSourceCode(eip_for,
-                                    $"While True",
-                                    $"If {first} Then",
-                                    $"{first} = False",
-                                    $"Else",
-                                    $"{stop} = Number({m.Groups["stop"]})",
-                                    $"If {counter} = {stop} Then",
-                                    $"ExitLoop",
-                                    $"EndIf",
-                                    $"{counter} += {step}",
-                                    $"EndIf"
-                                );
-                                _instruction_pointer = eip_for - 1;
-
-                                return InterpreterResult.OK;
-                            }
-                        }
-
-                        return WellKnownError("error.no_matching_close", "For", loc_for);
-                    }
-                    else
-                        return WellKnownError("error.malformed_for_expr", m.Groups["start"]);
-                },
-                [REGEX_FORIN] = m =>
-                {
-                    string counter_variables = m.Groups["variable"].Value.Trim();
-
-                    if (counter_variables.Match($"^{REGEX_VARIABLE}$", out Match _))
-                        counter_variables = $"${VariableResolver.CreateTemporaryVariable().Name}, {counter_variables}";
-
-                    if (!counter_variables.Match(REGEX_FORIN_VARIABLES, out Match m_iterator_variables))
-                        return WellKnownError("error.unparsable_iteration_variable", m.Groups["variable"]);
-
-                    Union<InterpreterError, Variable> get_or_create(string group)
-                    {
-                        if (!VariableResolver.TryGetVariable(m_iterator_variables.Groups[group].Value, VariableSearchScope.Local, out Variable? var))
-                            var = VariableResolver.CreateVariable(CurrentLocation, m_iterator_variables.Groups[group].Value, false);
-
-                        if (var.IsConst)
-                            return WellKnownError("error.constant_assignment", var.Name, var.DeclaredLocation);
-                        else
-                            return var;
-                    }
-
-                    return get_or_create("key").Match(err => err, iterator_key =>
-                        get_or_create("value").Match(err => err, iterator_value =>
-                        {
-                            SourceLocation loc_for = CurrentLocation;
-                            int eip_for = _instruction_pointer;
-                            int depth = 1;
-
-                            while (MoveNext())
-                            {
-                                if (CurrentLineContent.Match(REGEX_NEXT, out Match _))
-                                    --depth;
-                                else if (CurrentLineContent.Match(REGEX_FOR, out Match _))
-                                    ++depth;
-
-                                if (depth == 0)
-                                {
-                                    string iterator = VariableResolver.CreateTemporaryVariable().Name;
-
-                                    InsertReplaceSourceCode(_instruction_pointer,
-                                        $"WEnd",
-                                        $"{nameof(InternalsFunctionProvider.__iterator_destroy)}(\"{iterator}\")"
-                                    );
-                                    InsertReplaceSourceCode(eip_for,
-                                        $"{nameof(InternalsFunctionProvider.__iterator_create)}(\"{iterator}\", {m.Groups["expression"]})",
-                                        // TODO
-                                        // else if (!(collection = (Variant)result_coll).IsIndexable)
-                                        //     return WellKnownError("error.invalid_forin_source", collection);
-                                        $"While {nameof(InternalsFunctionProvider.__iterator_canmove)}(\"{iterator}\")",
-                                        $"${iterator_key.Name} = {nameof(InternalsFunctionProvider.__iterator_currentkey)}(\"{iterator}\")",
-                                        $"${iterator_value.Name} = {nameof(InternalsFunctionProvider.__iterator_currentvalue)}(\"{iterator}\")",
-                                        $"{nameof(InternalsFunctionProvider.__iterator_movenext)}(\"{iterator}\")"
-                                    );
-                                    _instruction_pointer = eip_for - 1;
-
-                                    return InterpreterResult.OK;
-                                }
-                            }
-
-                            return WellKnownError("error.no_matching_close", "For", loc_for);
-                        }));
-                },
-                [REGEX_WITH] = m =>
-                {
-                    Union<InterpreterError, PARSABLE_EXPRESSION> parsed = ProcessAsRawExpression(m.Groups["variable"].Value);
-
-                    if (parsed.Is(out InterpreterError? error))
-                        return error;
-                    else if (parsed.Is(out PARSABLE_EXPRESSION? pexpr) && pexpr is PARSABLE_EXPRESSION.AnyExpression
-                    {
-                        Item: EXPRESSION.Variable
-                        {
-                            Item: VARIABLE variable
-                        }
-                    } && VariableResolver.TryGetVariable(variable, VariableSearchScope.Global, out Variable? withctx) && !withctx.IsConst)
-                    {
-                        _withcontext_stack.Push(withctx);
-
-                        return InterpreterResult.OK;
-                    }
-                    else
-                        return WellKnownError("error.invalid_with_target");
-                },
-                [REGEX_ENDWITH] = _ =>
-                {
-                    if (_withcontext_stack.TryPop(out Variable _))
-                        return InterpreterResult.OK;
-                    else
-                        return WellKnownError("error.unexpected_close", line, "With");
-                },
-                [REGEX_REDIM] = m =>
-                {
-                    Union<InterpreterError, PARSABLE_EXPRESSION>? parsed = ProcessAsRawExpression(m.Groups["expression"].Value);
-
-                    if (parsed.Is(out PARSABLE_EXPRESSION? expr) && expr is PARSABLE_EXPRESSION.AnyExpression
-                    {
-                        Item: EXPRESSION.Indexer { Item: { Item1: EXPRESSION.Variable { Item: { Name: string varname } }, Item2: EXPRESSION index } }
-                    })
-                        if (VariableResolver.TryGetVariable(varname, VariableSearchScope.Global, out Variable? variable) && !variable.IsConst)
-                        {
-                            Union<InterpreterError, Variant> size = ProcessExpression(index);
-
-                            if (size.Is(out Variant size_value) && variable.Value.ResizeArray(Interpreter, (int)size_value, out Variant? new_arr) && new_arr is Variant arr)
-                            {
-                                variable.Value = arr;
-
-                                return InterpreterResult.OK;
-                            }
-
-                            return WellKnownError("error.invalid_redim_size", index);
-                        }
-                        else
-                            return WellKnownError("error.invalid_redim_expression", varname);
-
-                    return parsed.As<InterpreterError>() ?? WellKnownError("error.invalid_redim_expression", m.Groups["expression"]);
-                },
-                [REGEX_DO] = _ =>
-                {
-                    SourceLocation do_loc = CurrentLocation;
-                    int eip_do = _instruction_pointer;
-                    int depth = 1;
-
-                    while (MoveNext())
-                        if (CurrentLineContent.Match(REGEX_DO, out Match _))
-                            ++depth;
-                        else if (CurrentLineContent.Match(REGEX_UNTIL, out Match m))
-                        {
-                            --depth;
-
-                            if (depth == 0)
-                            {
-                                InsertReplaceSourceCode(_instruction_pointer, "WEnd");
-
-                                Variable temp = VariableResolver.CreateTemporaryVariable();
-                                string first = '$' + temp.Name;
-
-                                temp.Value = Variant.True;
-
-                                InsertReplaceSourceCode(eip_do,
-                                    $"While ({first} Or Not({m.Groups["expression"]}))",
-                                    $"{first} = False"
-                                );
-                                _instruction_pointer = eip_do - 1;
-
-                                return InterpreterResult.OK;
-                            }
-                        }
-
-                    return WellKnownError("error.no_matching_close", "Do", do_loc);
-                },
-                [REGEX_UNTIL] = _ => WellKnownError("error.unexpected_close", "Until", "Do"), // REGEX_UNTIL is handled by the REGEX_DO-case
-                [REGEX_WHILE] = m =>
-                {
-                    Union<InterpreterError, Variant> result = ProcessAsVariant(m.Groups["expression"].Value);
-
-                    if (result.Is(out InterpreterError? error))
-                        return error;
-
-                    if (!result.As<Variant>().ToBoolean())
-                        return MoveToEndOf(BlockStatementType.While) ?? InterpreterResult.OK;
-                    else
-                        _while_stack.Push(InsertInternalJumpLabel());
-
-                    return InterpreterResult.OK;
-                },
-                [REGEX_WEND] = _ =>
-                {
-                    _while_stack.TryPop(out string? label);
-
-                    if (label is null)
-                        return WellKnownError("error.unexpected_close", "WEnd", "While");
-                    else if (MoveTo(label) is InterpreterError error)
-                        return error;
-
-                    RemoveInternalJumpLabel(label);
-
-                    --_instruction_pointer;
-
-                    return InterpreterResult.OK;
-                },
-                [REGEX_IF] = m =>
-                {
-                    Union<InterpreterError, Variant> condition = ProcessAsVariant(m.Groups["condition"].Value);
-                    bool elif = m.Groups["elif"].Length > 0;
-
-                    if (elif)
-                        if (_if_stack.TryPop(out bool cond))
-                        {
-                            if (cond)
-                                condition = Variant.False;
-                        }
-                        else
-                            return WellKnownError("error.missing_if");
-
-                    if (condition.Is(out InterpreterError? error))
-                        return error;
-                    else
-                    {
-                        bool cond = condition.As<Variant>().ToBoolean();
-
-                        _if_stack.Push(cond);
-
-                        if (!cond && MoveToEndOf(BlockStatementType.If) is InterpreterError err)
-                            return err;
-                    }
-
-                    return InterpreterResult.OK;
-                },
-                [REGEX_ELSE] = _ =>
-                {
-                    if (_if_stack.TryPop(out bool cond))
-                    {
-                        if (cond && MoveToEndOf(BlockStatementType.If) is InterpreterError error)
-                            return error;
-                    }
-                    else
-                        return WellKnownError("error.missing_if");
-
-                    return InterpreterResult.OK;
-                },
-                [REGEX_ENDIF] = m => _if_stack.TryPop(out _) ? InterpreterResult.OK : WellKnownError("error.unexpected_close", m.Value, BlockStatementType.If),
-                [REGEX_GOTO] = m =>
-                {
-                    if (Interpreter.CommandLineOptions.StrictMode)
-                        return WellKnownError("error.experimental.goto_instructions");
-
-                    return MoveTo(m.Groups["label"].Value) ?? InterpreterResult.OK;
-                },
-                [REGEX_CONTINUELOOP_EXITLOOP] = m =>
-                {
-                    bool exit = m.Groups["mode"].Value.Equals("exit", StringComparison.InvariantCultureIgnoreCase);
-                    int level = 1;
-
-                    if (m.Groups["level"].Length > 0)
-                    {
-                        Union<InterpreterError, Variant> parsed = ProcessAsVariant(m.Groups["level"].Value);
-
-                        if (parsed.Is(out InterpreterError? error))
-                            return error;
-
-                        level = (int)(Variant)parsed;
-                    }
-
-                    while (level-- > 0)
-                    {
-                        if (!_while_stack.TryPop(out string? label))
-                            return WellKnownError("error.unexpected_contexitloop", exit ? "ExitLoop" : "ContinueLoop");
-                        else
-                        {
-                            if ((exit ? MoveToEndOf(BlockStatementType.While) : MoveTo(label)) is InterpreterError error)
-                                return error;
-                        }
-
-                        RemoveInternalJumpLabel(label);
-
-                        --_instruction_pointer;
-                    }
-
-                    return InterpreterResult.OK;
-                },
-                [REGEX_SELECT] = _ =>
-                {
-                    _switchselect_stack.Push((null, false));
-
-                    if (MoveToEndOf(BlockStatementType.Select) is InterpreterError error)
-                        return error;
-
-                    --_instruction_pointer;
-
-                    return InterpreterResult.OK;
-                },
-                [REGEX_SWITCH] = m =>
-                {
-                    Union<InterpreterError, Variant> expression = ProcessAsVariant(m.Groups["expression"].Value);
-
-                    if (expression.Is(out InterpreterError? error))
-                        return error;
-                    else
-                        _switchselect_stack.Push(((Variant)expression, false));
-
-                    error = MoveToEndOf(BlockStatementType.Switch);
-
-                    if (error is null)
-                        --_instruction_pointer;
-
-                    return error ?? InterpreterResult.OK;
-                },
-                [REGEX_ENDSELECT] = m =>
-                {
-                    if (_switchselect_stack.TryPop(out (Variant? expr, bool) topmost) && topmost.expr is null)
-                        return InterpreterResult.OK;
-                    else
-                        return WellKnownError("error.unexpected_close", m.Value, BlockStatementType.Select);
-                },
-                [REGEX_ENDSWITCH] = m =>
-                {
-                    if (_switchselect_stack.TryPop(out (Variant? expr, bool) topmost) && topmost.expr is Variant)
-                        return InterpreterResult.OK;
-                    else
-                        return WellKnownError("error.unexpected_close", m.Value, BlockStatementType.Switch);
-                },
-                [REGEX_CASE] = m =>
-                {
-                    Variant? switch_expr = null;
-
-                    if (!_switchselect_stack.TryPeek(out (Variant? switch_expr, bool handled) topmost))
-                        return WellKnownError("error.unexpected_case");
-                    else if (topmost.handled)
-                    {
-                        if (MoveToEndOf(switch_expr is null ? BlockStatementType.Select : BlockStatementType.Switch) is InterpreterError error)
-                            return error!;
-                        else
-                            --_instruction_pointer;
-
-                        return InterpreterResult.OK;
-                    }
-                    else if (REGEX_ELSE.IsMatch(m.Groups["expression"].Value))
-                        return InterpreterResult.OK;
-                    else
-                        switch_expr = topmost.switch_expr;
-
-                    Union<InterpreterError, PARSABLE_EXPRESSION> case_expr = ProcessAsRawExpression(m.Groups["expression"].Value);
-                    InterpreterResult process_success(bool success)
-                    {
-                        _switchselect_stack.TryPop(out topmost);
-                        _switchselect_stack.Push((topmost.switch_expr, success));
-
-                        if (!success)
-                            if (MoveToEndOf(BlockStatementType.Switch) is InterpreterError error)
-                                return error!;
-                            else
-                                --_instruction_pointer;
-
-                        return InterpreterResult.OK;
-                    }
-
-                    if (case_expr.Is(out PARSABLE_EXPRESSION? expression))
-                        if (expression is PARSABLE_EXPRESSION.ToExpression { Item1: EXPRESSION from, Item2: EXPRESSION to })
-                        {
-                            if (switch_expr is Variant sw)
-                                return ProcessExpression(from).Match(err => err!, from =>
-                                       ProcessExpression(to).Match(err => err!, to => process_success(from <= sw && sw <= to)));
-                            else
-                                return WellKnownError("error.invalid_case_range", expression);
-                        }
-                        else if (expression is PARSABLE_EXPRESSION.AnyExpression { Item: EXPRESSION expr })
-                            return ProcessExpression(expr).Match(err => err!, expr => process_success(switch_expr is Variant sw ? expr.EqualsCaseInsensitive(sw) : expr.ToBoolean()));
-                        else
-                            return WellKnownError("error.invalid_case_expr", expression);
-
-                    return (InterpreterError)case_expr;
-                },
-                [REGEX_CONTINUECASE] = _ =>
-                {
-                    if (!_switchselect_stack.TryPeek(out (Variant? switch_expr, bool) topmost))
-                        return WellKnownError("error.unexpected_continuecase");
-                    else if (MoveToEndOf(topmost.switch_expr is null ? BlockStatementType.Select : BlockStatementType.Switch) is InterpreterError error)
-                        return error;
-                    else if (!REGEX_CASE.IsMatch(CurrentLineContent))
-                        _switchselect_stack.TryPop(out topmost);
-
-                    return InterpreterResult.OK;
-                },
-            });
-
-            foreach (AbstractStatementProcessor? proc in Interpreter.PluginLoader.StatementProcessors)
-                if (proc is { Regex: Regex pat } sp && line.Match(pat, out Match _))
-                    result ??= sp.ProcessStatement(this, line);
-
-            return result;
-        });
-
-        private InterpreterError? ProcessExpressionStatement(string line) => Interpreter.Telemetry.Measure(TelemetryCategory.ProcessExpressionStatement, delegate
-        {
-            try
-            {
-                if (ProcessDeclarationModifiers(ref line, out DeclarationType declaration_type, out (char op, int amount)? enum_step) is { } err)
-                    return err;
-
-                ParserConstructor<PARSABLE_EXPRESSION>.ParserWrapper? provider = declaration_type is DeclarationType.None ? Interpreter.ParserProvider.ExpressionParser : Interpreter.ParserProvider.MultiDeclarationParser;
-                PARSABLE_EXPRESSION? expression = provider.Parse(line).ParsedValue;
-
-                MainProgram.PrintfDebugMessage("debug.au3thread.expr_statement", expression);
-
-                if (declaration_type == DeclarationType.None)
-                    return ProcessAssignmentStatement(expression, false).Match(Generics.id, _ => null);
-                else if (expression is PARSABLE_EXPRESSION.MultiDeclarationExpression multi_decl)
-                    return ProcessMultiDeclarationExpression(multi_decl, declaration_type, enum_step);
-                else
-                    return WellKnownError("error.invalid_multi_decl", line);
-            }
-            catch (Exception ex)
-            {
-                return Interpreter.Telemetry.Measure(TelemetryCategory.Exceptions, delegate
-                {
-                    if (Interpreter.CommandLineOptions.Verbosity > Verbosity.q)
-                        return new InterpreterError(CurrentLocation, $"{Interpreter.CurrentUILanguage["error.unparsable_line", line, ex.Message]}\n\nStack trace:\n{ex.StackTrace}");
-                    else
-                        return WellKnownError("error.unparsable_line", line, ex.Message);
-                });
-            }
-        });
-
-        private Union<InterpreterError, PARSABLE_EXPRESSION> ProcessAsRawExpression(string expression) =>
-            Interpreter.Telemetry.Measure<Union<InterpreterError, PARSABLE_EXPRESSION>>(TelemetryCategory.ProcessExpression, delegate
-            {
-                try
-                {
-                    ParserConstructor<PARSABLE_EXPRESSION>.ParserWrapper? provider = Interpreter.ParserProvider.ExpressionParser;
-                    PARSABLE_EXPRESSION parsed = provider.Parse(expression).ParsedValue;
-
-                    MainProgram.PrintfDebugMessage("debug.au3thread.raw_expr", parsed);
-
-                    return parsed;
-                }
-                catch (Exception ex)
-                {
-                    return Interpreter.Telemetry.Measure(TelemetryCategory.Exceptions, () => WellKnownError("error.unparsable_line", expression, ex.Message));
-                }
-            });
-
-        internal Union<InterpreterError, Variant> ProcessAsVariant(string expression)
-        {
-            Union<InterpreterError, PARSABLE_EXPRESSION>? result = ProcessAsRawExpression(expression);
-
-            if (result.Is(out PARSABLE_EXPRESSION.AnyExpression? any))
-            {
-                EXPRESSION folded = Interpreter.Telemetry.Measure(TelemetryCategory.ExpressionCleanup, () => Cleanup.FoldConstants(any.Item));
-
-                return ProcessExpression(folded);
-            }
-            else
-                return (InterpreterError?)result ?? WellKnownError("error.unparsable_line", expression);
-        }
-
-        private InterpreterError? ProcessDeclarationModifiers(ref string line, out DeclarationType declaration_type, out (char op, int amount)? enum_step)
-        {
-            declaration_type = DeclarationType.None;
-            enum_step = null;
-
-            while (line.Match(REGEX_DECLARATION_MODIFIER, out Match m_modifier))
-            {
-                DeclarationType modifier = (DeclarationType)Enum.Parse(typeof(DeclarationType), m_modifier.Value, true);
-
-                if (declaration_type.HasFlag(modifier))
-                    return WellKnownError("error.duplicate_modifier", modifier);
-
-                if (modifier is DeclarationType.Step)
-                    if (line.Match(REGEX_ENUM_STEP, out Match m_step))
-                    {
-                        char op = '+';
-                        int amount = int.Parse(m_step.Groups["step"].Value);
-
-                        if (m_step.Groups["op"] is { Length: > 0, Value: string s })
-                            op = s[0];
-
-                        enum_step = (op, amount);
-                    }
-                    else
-                        return WellKnownError("error.invalid_step", new string(line.TakeWhile(c => !char.IsWhiteSpace(c)).ToArray()));
-
-                declaration_type |= modifier;
-                line = line[m_modifier.Length..].TrimStart();
-            }
-
-            if (declaration_type.HasFlag(DeclarationType.Step) && !declaration_type.HasFlag(DeclarationType.Enum))
-                return WellKnownError("error.unexpected_step");
-
-            foreach ((DeclarationType m1, DeclarationType m2) in new[]
-            {
-                (DeclarationType.Dim, DeclarationType.Global),
-                (DeclarationType.Dim, DeclarationType.Local),
-                (DeclarationType.Dim, DeclarationType.Static),
-                (DeclarationType.Enum, DeclarationType.Static),
-                (DeclarationType.Local, DeclarationType.Global),
-                (DeclarationType.Static, DeclarationType.Const),
-            })
-                if (declaration_type.HasFlag(m1) && declaration_type.HasFlag(m2))
-                    return WellKnownError("error.incomplatible_modifiers", m1, m2);
-
-            return null;
-        }
-
-        private InterpreterError? ProcessMultiDeclarationExpression(PARSABLE_EXPRESSION.MultiDeclarationExpression multi_decl, DeclarationType decltype, (char op, int amount)? enum_step) =>
-            Interpreter.Telemetry.Measure(TelemetryCategory.ProcessDeclaration, delegate
-            {
-                InterpreterError? error = null;
-                Variable? variable;
-
-                foreach ((VARIABLE variable_ast, VARIABLE_DECLARATION declaration) in multi_decl.Item.Select(t => t.ToValueTuple()))
-                {
-                    error ??= ProcessVariableDeclaration(variable_ast, decltype);
-
-                    switch (declaration)
-                    {
-                        case VARIABLE_DECLARATION.Scalar { Item: null }:
-                            if (decltype.HasFlag(DeclarationType.Const))
-                                return WellKnownError("error.uninitialized_constant", variable_ast);
-                            else
-                                break;
-                        case VARIABLE_DECLARATION.Scalar { Item: FSharpOption<EXPRESSION> { Value: EXPRESSION expression } }:
-                            {
-                                // TODO : enum step handling
-
-                                var assg_expr = (ASSIGNMENT_TARGET.NewVariableAssignment(variable_ast), OPERATOR_ASSIGNMENT.Assign, expression).ToTuple();
-                                Union<InterpreterError, Variant> result = ProcessAssignmentStatement(PARSABLE_EXPRESSION.NewAssignmentExpression(assg_expr), true);
-
-                                if (result.Is(out Variant value))
-                                    MainProgram.PrintDebugMessage($"{variable_ast} = {value}");
-                                else
-                                    error ??= (InterpreterError)result;
-                            }
-                            break;
-                        case VARIABLE_DECLARATION.Array { Item1: int size, Item2: FSharpList<EXPRESSION> items }:
-                            if (size < 0)
-                                return WellKnownError("error.invalid_array_size", variable_ast, size);
-                            else if (items.Length > size)
-                                return WellKnownError("error.too_many_array_items", variable_ast, size, items.Length);
-                            else if (VariableResolver.TryGetVariable(variable_ast, VariableSearchScope.Global, out variable))
-                            {
-                                variable.Value = Variant.NewArray(size);
-
-                                int index = 0;
-
-                                foreach (EXPRESSION item in items)
-                                {
-                                    Union<InterpreterError, Variant> result = ProcessExpression(item);
-
-                                    if (result.Is(out error))
-                                        return error;
-
-                                    variable.Value.TrySetIndexed(Interpreter, index, result);
-                                    ++index;
-                                }
-
-                                break;
-                            }
-                            else
-                                return WellKnownError("error.undeclared_variable", variable_ast);
-                        case VARIABLE_DECLARATION.Map:
-                            if (VariableResolver.TryGetVariable(variable_ast, VariableSearchScope.Global, out variable))
-                            {
-                                variable.Value = Variant.NewMap();
-
-                                break;
-                            }
-                            else
-                                return WellKnownError("error.undeclared_variable", variable_ast);
-                        default:
-                            return WellKnownError("error.not_yet_implemented", declaration);
-                    }
-                }
-
-                return error;
-            });
-
-        private InterpreterError? ProcessVariableDeclaration(VARIABLE variable, DeclarationType decltype)
-        {
-            bool constant = decltype.HasFlag(DeclarationType.Const) || decltype.HasFlag(DeclarationType.Enum);
-            bool global = decltype.HasFlag(DeclarationType.Global) && !decltype.HasFlag(DeclarationType.Local);
-
-            if (decltype.HasFlag(DeclarationType.Static) && !global)
-                return WellKnownError("error.not_yet_implemented", "static"); // TODO : static
-
-            VariableScope scope = (global ? VariableResolver.GlobalRoot : null) ?? VariableResolver;
-
-            // if (decltype.HasFlag(DeclarationType.Dim) || decltype == DeclarationType.None)
-            //     global = CurrentFunction.IsMainFunction;
-
-            if (scope.TryGetVariable(variable, VariableSearchScope.Global, out Variable? var))
-            {
-                if (!(var.IsGlobal && decltype.HasFlag(DeclarationType.Local))) // potential conflict
-                    if (constant && !var.IsConst)
-                        return WellKnownError("error.cannot_make_constant", var, var.DeclaredLocation);
-                    else if (var.IsConst)
-                        return WellKnownError("error.redefining_constant", var, var.DeclaredLocation);
-            }
-
-            scope.CreateVariable(CurrentLocation, variable, constant);
-
-            return null;
-        }
-
-        private Union<InterpreterError, Variant> ProcessAssignmentStatement(PARSABLE_EXPRESSION assignment, bool force) =>
-            Interpreter.Telemetry.Measure<Union<InterpreterError, Variant>>(TelemetryCategory.ProcessAssignment, delegate
-            {
-                (ASSIGNMENT_TARGET target, EXPRESSION expression) = Interpreter.Telemetry.Measure(TelemetryCategory.ExpressionCleanup, () => Cleanup.CleanUpExpression(assignment));
-
-                switch (target)
-                {
-                    case ASSIGNMENT_TARGET.VariableAssignment { Item: VARIABLE variable }:
-                        {
-                            if (VariableResolver.TryGetVariable(variable.Name, VariableSearchScope.Global, out Variable? target_variable))
-                            {
-                                if (target_variable.IsConst && !force)
-                                    return WellKnownError("error.constant_assignment", target_variable, target_variable.DeclaredLocation);
-                            }
-                            else
-                                target_variable = VariableResolver.CreateVariable(CurrentLocation, variable.Name, false);
-
-                            if (target_variable is null)
-                                return WellKnownError("error.invalid_assignment_target", target);
-                            else
-                                return ProcessVariableAssignment(target_variable, expression);
-                        }
-                    case ASSIGNMENT_TARGET.IndexedAssignment { Item: { } indexer }:
-                        return ProcessExpression(indexer.Item1).Match<Union<InterpreterError, Variant>>(err => err, target =>
-                               ProcessExpression(indexer.Item2).Match<Union<InterpreterError, Variant>>(err => err, key =>
-                               ProcessExpression(expression).Match<Union<InterpreterError, Variant>>(err => err, value =>
-                               {
-                                   if (target.TrySetIndexed(Interpreter, key, value))
-                                       return value;
-
-                                   return WellKnownError("error.invalid_index_assg", target.AssignedTo, key);
-                               })));
-                    case ASSIGNMENT_TARGET.MemberAssignemnt { Item: MEMBER_EXPRESSION.ExplicitMemberAccess { Item1: { } targ, Item2: { Item: string memb } } }:
-                        return ProcessExpression(targ).Match<Union<InterpreterError, Variant>>(err => err, target =>
-                               ProcessExpression(expression).Match<Union<InterpreterError, Variant>>(err => err, value =>
-                               {
-                                   if (target.TrySetMember(Interpreter, memb, value) || target.TrySetIndexed(Interpreter, memb, value))
-                                       return value;
-
-                                   return WellKnownError("error.invalid_index_assg", target.AssignedTo, memb);
-                               }));
-                    case ASSIGNMENT_TARGET.MemberAssignemnt { Item: MEMBER_EXPRESSION.ImplicitMemberAccess { Item: { Item: string member } } }:
-                        {
-                            if (_withcontext_stack.TryPeek(out Variable? variable))
-                                return ProcessExpression(expression).Match<Union<InterpreterError, Variant>>(err => err, value =>
-                                {
-                                    if (variable.Value.TrySetMember(Interpreter, member, value) || variable.Value.TrySetIndexed(Interpreter, member, value))
-                                        return value;
-
-                                    return WellKnownError("error.invalid_index_assg", variable, member);
-                                });
-                            else
-                                return WellKnownError("error.invalid_with_access", member);
-                        }
-                    default:
-                        return WellKnownError("error.invalid_assignment_target", target);
-                }
-            });
-
-        private Union<InterpreterError, Variant> ProcessVariableAssignment(Variable variable, EXPRESSION expression)
-        {
-            foreach (VARIABLE v in expression.ReferencedVariables)
-                if (!VariableResolver.HasVariable(v, VariableSearchScope.Global))
-                    return WellKnownError("error.undeclared_variable", v);
-
-            Union<InterpreterError, Variant> value = ProcessExpression(expression);
-
-            if (value.Is(out Variant variant))
-                (variable.ReferencedVariable ?? variable).Value = variant;
-
-            return value;
-        }
-
-        private Union<InterpreterError, Variant> ProcessExpression(EXPRESSION? expression) =>
-            Interpreter.Telemetry.Measure(TelemetryCategory.EvaluateExpression, delegate
-            {
-                Union<InterpreterError, Variant> value = expression switch
-                {
-                    null => Variant.Null,
-                    EXPRESSION.Literal { Item: LITERAL literal } => ProcessLiteral(literal),
-                    EXPRESSION.Variable { Item: VARIABLE variable } => ProcessVariable(variable),
-                    EXPRESSION.Macro { Item: MACRO macro } => ProcessMacro(macro),
-                    EXPRESSION.FunctionName { Item: { Item: string func_name } } =>
-                        Interpreter.ScriptScanner.TryResolveFunction(func_name) is ScriptFunction func
-                        ? (Union<InterpreterError, Variant>)Variant.FromFunction(func)
-                        : (Union<InterpreterError, Variant>)WellKnownError("error.unresolved_func", func_name),
-                    EXPRESSION.Unary { Item: Tuple<OPERATOR_UNARY, EXPRESSION> unary } => ProcessUnary(unary.Item1, unary.Item2),
-                    EXPRESSION.Binary { Item: Tuple<EXPRESSION, OPERATOR_BINARY, EXPRESSION> binary } => ProcessBinary(binary.Item1, binary.Item2, binary.Item3),
-                    EXPRESSION.Ternary { Item: Tuple<EXPRESSION, EXPRESSION, EXPRESSION> ternary } => ProcessTernary(ternary.Item1, ternary.Item2, ternary.Item3),
-                    EXPRESSION.Member { Item: MEMBER_EXPRESSION member } => ProcessMember(member),
-                    EXPRESSION.Indexer { Item: Tuple<EXPRESSION, EXPRESSION> indexer } => ProcessIndexer(indexer.Item1, indexer.Item2),
-                    EXPRESSION.FunctionCall { Item: FUNCCALL_EXPRESSION funccall } => ProcessFunctionCall(funccall),
-                    _ => WellKnownError("error.not_yet_implemented", expression),
-                };
-
-                if (value.Is(out Variant v))
-                    MainProgram.PrintfDebugMessage("debug.au3thread.expression", expression, v.ToDebugString(Interpreter));
-
-                return value;
-            });
-
-        private Union<InterpreterError, Variant> ProcessIndexer(EXPRESSION expr, EXPRESSION index) =>
-            ProcessExpression(expr).Match<Union<InterpreterError, Variant>>(err => err, @object =>
-            ProcessExpression(index).Match<Union<InterpreterError, Variant>>(err => err, key =>
-            {
-                if (@object.TryGetIndexed(Interpreter, key, out Variant value))
-                    return value;
-
-                return WellKnownError("error.invalid_index", key);
-            }));
-
-        private Union<InterpreterError, Variant> ProcessMember(MEMBER_EXPRESSION expr)
-        {
-            Union<InterpreterError, Variant> result = WellKnownError("error.not_yet_implemented", expr);
-            string? member = null;
-
-            switch (expr)
-            {
-                case MEMBER_EXPRESSION.ExplicitMemberAccess { Item1: { } objexpr, Item2: { Item: string m } }:
-                    result = ProcessExpression(objexpr);
-                    member = m;
-
-                    break;
-                case MEMBER_EXPRESSION.ImplicitMemberAccess { Item: { Item: string m } }:
-                    if (_withcontext_stack.TryPeek(out Variable? variable))
-                    {
-                        result = variable.Value;
-                        member = m;
-
-                        break;
-                    }
-                    else
-                        return WellKnownError("error.invalid_with_access", m);
-            }
-
-            if (result.Is(out Variant value) && member is string)
-            {
-                if (value.TryGetMember(Interpreter, member, out Variant v))
-                    result = v;
-                else if (value.TryGetIndexed(Interpreter, member, out v))
-                    result = v;
-                else if (member.Equals("length", StringComparison.InvariantCultureIgnoreCase))
-                    result = (Variant)value.Length;
-                else
-                    return WellKnownError("error.unknown_member", member);
-            }
-            
-            return result;
-        }
-
-        private Union<InterpreterError, Variant> ProcessUnary(OPERATOR_UNARY op, EXPRESSION expr)
-        {
-            Union<InterpreterError, Variant> result = ProcessExpression(expr);
-
-            if (result.Is(out Variant value))
-                if (op.IsIdentity)
-                    result = +value;
-                else if (op.IsNegate)
-                    result = -value;
-                else if (op.IsNot)
-                    result = !value;
-                else if (op is OPERATOR_UNARY.Cast { Item: { } cop })
-                    if (cop.IsCBool)
-                        result = (Variant)value.ToBoolean();
-                    else if (cop.IsCInt)
-                        result = (Variant)(int)value.ToNumber();
-                    else if (cop.IsCNumber)
-                        result = (Variant)value.ToNumber();
-                    else if (cop.IsCString)
-                        result = (Variant)value.ToString();
-                    else if (cop.IsCBinary)
-                        result = (Variant)value.ToBinary();
-                    else
-                        result = WellKnownError("error.unsupported_operator", cop);
-                else
-                    result = WellKnownError("error.unsupported_operator", op);
-
-            return result;
-        }
-
-        private Union<InterpreterError, Variant> ProcessBinary(EXPRESSION expr1, OPERATOR_BINARY op, EXPRESSION expr2)
-        {
-            InterpreterError? evaluate(EXPRESSION expr, out Variant target)
-            {
-                Union<InterpreterError, Variant> result = ProcessExpression(expr);
-
-                target = Variant.Zero;
-
-                if (result.Is(out InterpreterError? error))
-                    return error;
-
-                target = (Variant)result;
-
-                return null;
-            }
-
-            InterpreterError? err = evaluate(expr1, out Variant e1);
-            Variant e2;
-
-            if (err is { })
-                return err;
-            else if (op.IsAnd)
-            {
-                if (!e1.ToBoolean())
-                    return Variant.False;
-                else if ((err = evaluate(expr2, out e2)) is { })
-                    return err;
-                else
-                    return e2;
-            }
-            else if (op.IsOr)
-            {
-                if (e1.ToBoolean())
-                    return Variant.True;
-                else if ((err = evaluate(expr2, out e2)) is { })
-                    return err;
-                else
-                    return e2;
-            }
-            else
-                err = evaluate(expr2, out e2);
-
-            if (err is { })
-                return err;
-            else if (op.IsStringConcat)
-                return e1 & e2;
-            else if (op.IsEqualCaseSensitive)
-                return Variant.FromBoolean(e1.EqualsCaseSensitive(e2));
-            else if (op.IsEqualCaseInsensitive)
-                return Variant.FromBoolean(e1.EqualsCaseInsensitive(e2));
-            else if (op.IsUnequal)
-                return Variant.FromBoolean(e1.NotEquals(e2));
-            else if (op.IsGreater)
-                return Variant.FromBoolean(e1 > e2);
-            else if (op.IsGreaterEqual)
-                return Variant.FromBoolean(e1 >= e2);
-            else if (op.IsLower)
-                return Variant.FromBoolean(e1 < e2);
-            else if (op.IsLowerEqual)
-                return Variant.FromBoolean(e1 <= e2);
-            else if (op.IsAdd)
-                return e1 + e2;
-            else if (op.IsSubtract)
-                return e1 - e2;
-            else if (op.IsMultiply)
-                return e1 * e2;
-            else if (op.IsDivide)
-                return e1 / e2;
-            else if (op.IsPower)
-                return e1 ^ e2;
-
-            // TODO : modulus
-
-            return WellKnownError("error.unsupported_operator", op);
-        }
-
-        private Union<InterpreterError, Variant> ProcessTernary(EXPRESSION expr1, EXPRESSION expr2, EXPRESSION expr3) =>
-            ProcessExpression(expr1).Match<Union<InterpreterError, Variant>>(e => e, cond => ProcessExpression(cond.ToBoolean() ? expr2 : expr3));
-
-        private Union<InterpreterError, Variant> ProcessFunctionCall(FUNCCALL_EXPRESSION funccall)
-        {
-            Union<Variant[], InterpreterError> ProcessRawArguments(FSharpList<EXPRESSION> raw_args)
-            {
-                Variant[] arguments = new Variant[raw_args.Length];
-                int i = 0;
-
-                foreach (EXPRESSION arg in raw_args)
-                {
-                    Union<InterpreterError, Variant>? res = ProcessExpression(arg);
-
-                    if (res.Is(out Variant value))
-                        arguments[i++] = value;
-                    else
-                        return (InterpreterError)res;
-                }
-
-                return arguments;
-            }
-
-            switch (funccall)
-            {
-                case FUNCCALL_EXPRESSION.DirectFunctionCall { Item1: { Item: string func_name }, Item2: var raw_args }:
-                    if (Interpreter.ScriptScanner.TryResolveFunction(func_name) is ScriptFunction func)
-                        return ProcessRawArguments(raw_args).Match<Union<InterpreterError, Variant>>(args => Call(func, args), err => err);
-                    else
-                        return WellKnownError("error.unresolved_func", func_name);
-                case FUNCCALL_EXPRESSION.MemberCall member_call:
-                    throw new NotImplementedException();
-            }
-
-            return WellKnownError("error.not_yet_implemented", funccall);
-        }
-
-        private Union<InterpreterError, Variant> ProcessMacro(MACRO macro)
-        {
-            string name = macro.Name;
-
-            foreach (AbstractMacroProvider provider in Interpreter.PluginLoader.MacroProviders)
-                if (provider.ProvideMacroValue(this, name, out Variant? value) && value.HasValue)
-                    return value.Value;
-
-            return WellKnownError("error.unknown_macro", macro.Name);
-        }
-
-        private Union<InterpreterError, Variant> ProcessVariable(VARIABLE variable)
-        {
-            if (variable == VARIABLE.Discard)
-                return WellKnownError("error.invalid_discard_access", VARIABLE.Discard, FrameworkMacros.MACRO_DISCARD);
-
-            if (VariableResolver.TryGetVariable(variable, VariableSearchScope.Global, out Variable? var))
-            {
-                Variant value = var.Value;
-
-                if (value.AssignedTo != var)
-                    var.Value = value.AssignTo(var); // update parent var
-
-                return value;
-            }
-            else
-                return WellKnownError("error.undeclared_variable", variable);
-        }
-
-        private Variant ProcessLiteral(LITERAL literal) => Variant.FromLiteral(literal); // TODO : on error throw ?
-
-        private InterpreterResult? UseExternalLineProcessors(string line)
-        {
-            foreach (AbstractLineProcessor proc in Interpreter.PluginLoader.LineProcessors)
-                if (proc.CanProcessLine(line) && Interpreter.Telemetry.Measure(TelemetryCategory.ExternalProcessor, () => proc.ProcessLine(this, line)) is { } res)
-                    return res;
-
-            return null;
-        }
-
-        private InterpreterError WellKnownError(string key, params object?[] args) => InterpreterError.WellKnown(CurrentLocation, key, args);
-    }
-
-    [Flags]
-    public enum DeclarationType
-        : byte
-    {
-        None = 0b_0000_0000,
-        Dim = 0b_0000_0001,
-        Local = 0b_0000_0010,
-        Global = 0b_0000_0100,
-        Const = 0b_0000_1000,
-        Static = 0b_0001_0000,
-        Enum = 0b_0010_0000,
-        Step = 0b_0100_0000,
-    }
-
-    public enum BlockStatementType
-        : int
-    {
-        __function__ = default,
-        While,
-        If,
-        Select,
-        Switch,
-        // Case,
-    }
 }
diff --git a/new/AutoItInterpreter/Runtime/CallFrame.cs b/new/AutoItInterpreter/Runtime/CallFrame.cs
new file mode 100644
index 00000000..e02ffde9
--- /dev/null
+++ b/new/AutoItInterpreter/Runtime/CallFrame.cs
@@ -0,0 +1,1579 @@
+using System.Text.RegularExpressions;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+using System;
+
+using Microsoft.FSharp.Collections;
+using Microsoft.FSharp.Core;
+
+using Piglet.Parser.Configuration.Generic;
+
+using Unknown6656.AutoIt3.Extensibility.Plugins.Au3Framework;
+using Unknown6656.AutoIt3.Extensibility.Plugins.Internals;
+using Unknown6656.AutoIt3.ExpressionParser;
+using Unknown6656.AutoIt3.Extensibility;
+using Unknown6656.Common;
+
+using static Unknown6656.AutoIt3.ExpressionParser.AST;
+
+namespace Unknown6656.AutoIt3.Runtime
+{
+#pragma warning disable CA1063
+    // TODO : covariant return for 'CurrentFunction'
+    public abstract class CallFrame
+        : IDisposable
+    {
+        public AU3Thread CurrentThread { get; }
+
+        public virtual ScriptFunction CurrentFunction { get; }
+
+        public VariableScope VariableResolver { get; }
+
+        public Variant[] PassedArguments { get; }
+
+        public CallFrame? CallerFrame { get; }
+
+        public Variant ReturnValue { protected set; get; } = Variant.Zero;
+
+        public virtual SourceLocation CurrentLocation => CurrentThread.CurrentLocation ?? CurrentFunction.Location;
+
+        public Interpreter Interpreter => CurrentThread.Interpreter;
+
+
+        internal CallFrame(AU3Thread thread, CallFrame? caller, ScriptFunction function, Variant[] args)
+        {
+            CurrentThread = thread;
+            CallerFrame = caller;
+            CurrentFunction = function;
+            PassedArguments = args;
+
+            // TODO : the following line is wrong - it should be interpreter as parent, not the previous frame
+            VariableResolver = function.IsMainFunction ? thread.CurrentVariableResolver : thread.CurrentVariableResolver.CreateChildScope(this);
+        }
+
+        public void Dispose() => VariableResolver.Dispose();
+
+        protected abstract Union<InterpreterError, Variant> InternalExec(Variant[] args);
+
+        internal Union<InterpreterError, Variant> Execute(Variant[] args)
+        {
+            Union<InterpreterError, Variant> result = Variant.Zero;
+            ScannedScript script = CurrentFunction.Script;
+
+            SetError(0, 0);
+
+            Interpreter.Telemetry.Measure(TelemetryCategory.OnAutoItStart, delegate
+            {
+                if (CurrentFunction.IsMainFunction && script.LoadScript(this) is InterpreterError load_error)
+                    result = load_error;
+            });
+
+            (int min_argc, int max_argc) = CurrentFunction.ParameterCount;
+
+            if (args.Length < min_argc)
+                return InterpreterError.WellKnown(CurrentThread.CurrentLocation, "error.not_enough_args", CurrentFunction.Name, min_argc, args.Length);
+            else if (args.Length > max_argc)
+                return InterpreterError.WellKnown(CurrentThread.CurrentLocation, "error.too_many_args", CurrentFunction.Name, max_argc, args.Length);
+            else if (result.Is<Variant>())
+                if (CurrentThread.IsRunning)
+                {
+                    MainProgram.PrintfDebugMessage("debug.au3thread.executing", CurrentFunction);
+
+                    result = Interpreter.Telemetry.Measure(TelemetryCategory.ScriptExecution, () => InternalExec(args));
+                }
+
+            Interpreter.Telemetry.Measure(TelemetryCategory.OnAutoItExit, delegate
+            {
+                if (CurrentFunction.IsMainFunction && result.Is<Variant>() && script.UnLoadScript(this) is InterpreterError unload_error)
+                    result = unload_error;
+            });
+
+            if (result.Is(out Variant @return))
+                ReturnValue = @return;
+
+            return result;
+        }
+
+        public Union<InterpreterError, Variant> Call(ScriptFunction function, Variant[] args) => CurrentThread.Call(function, args);
+
+        public Variant SetError(int error, Variant? extended = null, in Variant @return = default)
+        {
+            Interpreter.ErrorCode = error;
+
+            return SetExtended(extended, in @return);
+        }
+
+        public Variant SetExtended(Variant? extended, in Variant @return = default)
+        {
+            Interpreter.ExtendedValue = extended ?? Variant.Null;
+
+            return @return;
+        }
+
+        public void Print(Variant value) => Interpreter.Print(this, value);
+
+        public void Print(object? value) => Interpreter.Print(this, value);
+
+        public override string ToString() => $"[0x{CurrentThread.ThreadID:x4}]";
+
+        internal void IssueWarning(string key, params object?[] args) => MainProgram.PrintWarning(CurrentLocation, Interpreter.CurrentUILanguage[key, args]);
+    }
+#pragma warning restore CA1063
+
+    public sealed class NativeCallFrame
+        : CallFrame
+    {
+        internal NativeCallFrame(AU3Thread thread, CallFrame? caller, NativeFunction function, Variant[] args)
+            : base(thread, caller, function, args)
+        {
+        }
+
+        protected override Union<InterpreterError, Variant> InternalExec(Variant[] args)
+        {
+            FunctionReturnValue result = Interpreter.Telemetry.Measure(TelemetryCategory.NativeScriptExecution, () => ((NativeFunction)CurrentFunction).Execute(this, args));
+            Variant? extended = null;
+            int error = 0;
+
+            if (result.IsFatal(out InterpreterError? fatal))
+                return fatal;
+            else if (result.IsSuccess(out Variant variant, out extended) || result.IsError(out variant, out error, out extended))
+                return SetError(error, extended, in variant);
+            else
+                throw new InvalidOperationException("Return value could not be processed");
+        }
+
+        public override string ToString() => $"{base.ToString()} native call frame";
+    }
+
+    public sealed class AU3CallFrame
+        : CallFrame
+    {
+        private const RegexOptions _REGEX_OPTIONS = RegexOptions.IgnoreCase | RegexOptions.Compiled;
+        private static readonly Regex REGEX_INTERNAL_LABEL = new Regex(@"^§\w+$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_VARIABLE = new Regex(@"\$([^\W\d]|[^\W\d]\w*)\b", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_GOTO = new Regex(@"^goto\s+(?<label>.+)$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_WHILE = new Regex(@"^while\s+(?<expression>.+)$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_WEND = new Regex(@"^wend$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_NEXT = new Regex(@"^next$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_EXIT = new Regex(@"^exit(\b\s*(?<code>.+))?$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_RETURN = new Regex(@"^return(\b\s*(?<value>.+))?$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_FOR = new Regex(@"^for\s+.+$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_FORTO = new Regex(@"^for\s+(?<start>.+)\s+to\s+(?<stop>.+?)(\s+step\s+(?<step>.+))?$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_FORIN = new Regex(@"^for\s+(?<variable>.+)\s+in\s+(?<expression>.+)$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_FORIN_VARIABLES = new Regex(@"^\$(?<key>[^\W\d]|[^\W\d]\w*)\s*,\s*\$(?<value>[^\W\d]|[^\W\d]\w*)$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_WITH = new Regex(@"^with\s+(?<variable>.+)$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_ENDWITH = new Regex(@"^endwith$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_REDIM = new Regex(@"^redim\s+(?<expression>.+)$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_DO = new Regex(@"^do$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_UNTIL = new Regex(@"^until\s+(?<expression>.+)$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_IF = new Regex(@"^(?<elif>else)?if\s+(?<condition>.+)\s+then$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_ELSE = new Regex(@"^else$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_ENDIF = new Regex(@"^endif$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_DECLARATION_MODIFIER = new Regex(@"^(local|static|global|const|dim|enum|step)\b", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_ENUM_STEP = new Regex(@"^(?<op>[+\-*]?)(?<step>\d+)\b", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_INCLUDE = new Regex(@"^include?\s+(?<open>[""'<])(?<path>(?:(?!\k<close>).)+)(?<close>[""'>])$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_CONTINUELOOP_EXITLOOP = new Regex(@"^(?<mode>continue|exit)loop\s*(?<level>.+)?\s*$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_SELECT = new Regex(@"^select$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_ENDSELECT = new Regex(@"^endselect$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_SWITCH = new Regex(@"^switch\b\s*(?<expression>.+)$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_ENDSWITCH = new Regex(@"^endswitch$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_CASE = new Regex(@"^case\b\s*(?<expression>.+)*$", _REGEX_OPTIONS);
+        private static readonly Regex REGEX_CONTINUECASE = new Regex(@"^continuecase$", _REGEX_OPTIONS);
+
+        private readonly ConcurrentDictionary<string, IEnumerator<(Variant key, Variant value)>> _iterators = new();
+        private readonly ConcurrentStack<Variable> _withcontext_stack = new ConcurrentStack<Variable>();
+        private readonly ConcurrentStack<bool> _if_stack = new ConcurrentStack<bool>();
+        private readonly ConcurrentStack<string> _while_stack = new();
+        private readonly ConcurrentStack<(Variant? switch_expression, bool case_handled)> _switchselect_stack = new();
+
+        private volatile int _instruction_pointer = 0;
+        private List<(SourceLocation LineLocation, string LineContent)> _line_cache;
+
+
+        public int CurrentInstructionPointer => _instruction_pointer;
+
+        public (SourceLocation LineLocation, string LineContent)[] CurrentLineCache => _line_cache.ToArray();
+
+        public override SourceLocation CurrentLocation => _instruction_pointer < 0 ? CurrentFunction.Location : _line_cache[_instruction_pointer].LineLocation;
+
+        public string CurrentLineContent => _instruction_pointer < 0 ? '<' + Interpreter.CurrentUILanguage["general.unknown"] + '>' : _line_cache[_instruction_pointer].LineContent;
+
+        public Dictionary<string, int> InternalJumpLabels => _line_cache.WithIndex().Where(l => REGEX_INTERNAL_LABEL.IsMatch(l.Item.LineContent)).ToDictionary(l => l.Item.LineContent, l => l.Index);
+
+
+        internal AU3CallFrame(AU3Thread thread, CallFrame? caller, AU3Function function, Variant[] args)
+            : base(thread, caller, function, args)
+        {
+            _line_cache = function.Lines.ToList();
+            _instruction_pointer = 0;
+        }
+
+        public override string ToString() => $"{base.ToString()} {CurrentLocation}";
+
+        protected override Union<InterpreterError, Variant> InternalExec(Variant[] args)
+        {
+            _instruction_pointer = -1;
+
+            AU3Function func = (AU3Function)CurrentFunction;
+            int argc = func.ParameterCount.MaximumCount;
+            int len = args.Length;
+
+            if (len < argc)
+                Array.Resize(ref args, argc);
+
+            for (int i = 0; i < argc; ++i)
+            {
+                PARAMETER_DECLARATION param = func.Parameters[i];
+                Variable param_var = VariableResolver.CreateVariable(func.Location, param.Variable.Name, param.IsConst);
+
+                if (i < len)
+                {
+                    if (param.IsByRef && args[i].AssignedTo is Variable existing)
+                        if (existing.IsConst)
+                            return WellKnownError("error.constant_passed_as_ref", existing, i + 1);
+                        else
+                            args[i] = Variant.FromReference(existing);
+                }
+                else if (param.DefaultValue is null)
+                    return WellKnownError("error.missing_argument", i + 1, param.Variable);
+                else
+                {
+                    EXPRESSION expr = param.DefaultValue.Value;
+                    Union<InterpreterError, Variant> result = ProcessExpression(expr);
+
+                    if (result.Is(out InterpreterError? error))
+                        return error;
+                    else if (result.Is(out Variant value))
+                        args[i] = value;
+                }
+
+                param_var.Value = args[i];
+            }
+
+            return Interpreter.Telemetry.Measure<Union<InterpreterError, Variant>>(TelemetryCategory.Au3ScriptExecution, delegate
+            {
+                _instruction_pointer = 0;
+
+                while (_instruction_pointer < _line_cache.Count && CurrentThread.IsRunning)
+                    if (ParseCurrentLine()?.OptionalError is InterpreterError error)
+                        return error;
+                    else if (!MoveNext())
+                        break;
+
+                return ReturnValue;
+            });
+        }
+
+        private bool MoveNext()
+        {
+            if (_instruction_pointer < _line_cache.Count)
+            {
+                ++_instruction_pointer;
+
+                return true;
+            }
+            else
+                return false;
+        }
+
+        private bool MoveAfter(SourceLocation closest_location)
+        {
+            _instruction_pointer = (from ln in _line_cache.WithIndex()
+                                    let loc = ln.Item.LineLocation
+                                    where loc >= closest_location
+                                    orderby loc ascending
+                                    select ln.Index).FirstOrDefault();
+
+            return _instruction_pointer < _line_cache.Count;
+        }
+
+        private bool MoveBefore(SourceLocation closest_location)
+        {
+            MoveAfter(closest_location);
+            --_instruction_pointer;
+
+            return _instruction_pointer < _line_cache.Count;
+        }
+
+        private bool MoveTo(JumpLabel jump_label) => MoveAfter(jump_label.Location);
+
+        private InterpreterError? MoveTo(string jump_label)
+        {
+            if (InternalJumpLabels.TryGetValue(jump_label, out int index))
+            {
+                _instruction_pointer = index;
+
+                return null;
+            }
+            else if ((CurrentFunction as AU3Function)?.JumpLabels[jump_label] is JumpLabel label)
+            {
+                MoveTo(label);
+
+                return null;
+            }
+
+            return WellKnownError("error.unknown_jumplabel", jump_label);
+        }
+
+        /// <summary>
+        /// Copies the given value into the <see cref="CallFrame.ReturnValue"/>-field, and moves the instruction pointer to the end.
+        /// </summary>
+        /// <param name="value">Return value</param>
+        public void Return(Variant value)
+        {
+            _instruction_pointer = _line_cache.Count;
+            ReturnValue = value;
+        }
+
+        private bool RemoveInternalJumpLabel(string jump_label)
+        {
+            if (REGEX_INTERNAL_LABEL.IsMatch(jump_label))
+                for (int i = 0; i < _line_cache.Count; i++)
+                    if (jump_label.Equals(_line_cache[i].LineContent))
+                    {
+                        _line_cache.RemoveAt(i);
+
+                        return true;
+                    }
+
+            return false;
+        }
+
+        private string InsertInternalJumpLabel()
+        {
+            string name = $"§{Guid.NewGuid():N}";
+
+            if (_instruction_pointer < _line_cache.Count)
+                _line_cache.Insert(_instruction_pointer, (CurrentLocation, name));
+            else
+                _line_cache.Add((SourceLocation.Unknown, name));
+
+            ++_instruction_pointer;
+
+            return name;
+        }
+        
+        private void InsertReplaceSourceCode(int instruction_ptr, params string[] lines)
+        {
+            int eip = _instruction_pointer;
+
+            _instruction_pointer = instruction_ptr;
+
+            if (lines.Length == 1)
+            {
+                if (_instruction_pointer < _line_cache.Count)
+                    _line_cache[_instruction_pointer] = (CurrentLocation, lines[0]);
+                else
+                    _line_cache.Add((SourceLocation.Unknown, lines[0]));
+            }
+            else
+            {
+                _line_cache.RemoveAt(_instruction_pointer);
+
+                if (_instruction_pointer < _line_cache.Count)
+                    _line_cache.InsertRange(_instruction_pointer, lines.Select(l => (CurrentLocation, l)));
+                else
+                    _line_cache.AddRange(lines.Select(l => (SourceLocation.Unknown, l)));
+            }
+
+            _instruction_pointer = eip;
+        }
+
+        public InterpreterResult? ParseCurrentLine()
+        {
+            (SourceLocation loc, string line) = _line_cache[_instruction_pointer];
+            InterpreterResult? result = null;
+
+            line = line.Trim();
+
+            MainProgram.PrintDebugMessage("-----------------------------------------------------------------------------------------------");
+            MainProgram.PrintfDebugMessage("debug.au3thread.location", loc);
+            MainProgram.PrintfDebugMessage("debug.au3thread.content", line);
+
+            if (string.IsNullOrEmpty(line) || REGEX_INTERNAL_LABEL.IsMatch(line))
+                return InterpreterResult.OK;
+
+            Interpreter.Telemetry.Measure(TelemetryCategory.ProcessLine, delegate
+            {
+                result ??= ProcessDirective(line);
+                result ??= ProcessStatement(line);
+                result ??= UseExternalLineProcessors(line);
+                result ??= ProcessExpressionStatement(line);
+            });
+
+            if (Interpreter.CommandLineOptions.IgnoreErrors && result?.OptionalError?.Message is string msg)
+            {
+                MainProgram.PrintWarning(CurrentLocation, msg);
+
+                result = null;
+            }
+
+            return result ?? InterpreterResult.OK;
+        }
+
+        private InterpreterResult? ProcessDirective(string directive)
+        {
+            if (!directive.StartsWith('#'))
+                return null;
+
+            directive = directive[1..];
+
+            InterpreterResult? result = Interpreter.Telemetry.Measure(TelemetryCategory.ProcessDirective, delegate
+            {
+                if (directive.Match(REGEX_INCLUDE, out ReadOnlyIndexer<string, string>? g))
+                {
+                    char open = g["open"][0];
+                    char close = g["close"][0];
+                    bool relative = open != '<';
+
+                    if (open != close && open != '<' && close != '>')
+                        return WellKnownError("error.mismatched_quotes", open, close);
+
+                    return Interpreter.ScriptScanner.ScanScriptFile(CurrentLocation, g["path"], relative).Match(err => err, script =>
+                    {
+                        ScannedScript[] active = Interpreter.ScriptScanner.ActiveScripts;
+
+                        if (active.Contains(script))
+                        {
+                            if (script.IncludeOnlyOnce)
+                                return InterpreterResult.OK;
+                            else
+                                return WellKnownError("error.circular_include", script.Location.FullName);
+                        }
+                        else if (Call(script.MainFunction, Array.Empty<Variant>()).Is(out InterpreterError? err))
+                            return err;
+                        else
+                            return InterpreterResult.OK;
+                    });
+                }
+
+                return null;
+            });
+
+            foreach (AbstractDirectiveProcessor proc in Interpreter.PluginLoader.DirectiveProcessors)
+                result ??= Interpreter.Telemetry.Measure(TelemetryCategory.ProcessDirective, () => proc.ProcessDirective(this, directive));
+
+            if (result is null)
+                IssueWarning("warning.unparsable_dirctive", directive);
+
+            return InterpreterResult.OK;
+        }
+
+        private InterpreterError? MoveToEndOf(BlockStatementType type)
+        {
+            SourceLocation init = CurrentLocation;
+            int depth = 1;
+
+            if (type is BlockStatementType.If)
+                while (MoveNext())
+                {
+                    string line = CurrentLineContent.Trim();
+                    bool @if = false;
+
+                    if (line.Match(REGEX_IF, out Match m))
+                    {
+                        @if = true;
+
+                        if (m.Groups["elif"].Length > 0)
+                            --depth;
+                        else
+                            ++depth;
+                    }
+                    else if (REGEX_ELSE.IsMatch(line))
+                        --depth;
+                    else if (REGEX_ENDIF.IsMatch(line))
+                        --depth;
+
+                    if (depth == 0)
+                    {
+                        if (@if)
+                            --_instruction_pointer;
+
+                        break;
+                    }
+                }
+            else if (type is BlockStatementType.While or BlockStatementType.Select or BlockStatementType.Switch)
+            {
+                (Regex start, Regex end) = type switch
+                {
+                    BlockStatementType.Select => (REGEX_SELECT, REGEX_ENDSELECT),
+                    BlockStatementType.Switch => (REGEX_SWITCH, REGEX_ENDSWITCH),
+                    BlockStatementType.While => (REGEX_WHILE, REGEX_WEND),
+                    _ => throw new ArgumentOutOfRangeException(nameof(type)),
+                };
+
+                while (MoveNext())
+                {
+                    string line = CurrentLineContent.Trim();
+
+                    if (end.IsMatch(line))
+                        --depth;
+                    else if (type is not BlockStatementType.While && REGEX_CASE.IsMatch(line))
+                        --depth;
+                    else if (start.IsMatch(line))
+                        ++depth;
+
+                    if (depth == 0)
+                        break;
+                }
+            }
+
+            // TODO : other block types
+
+            else
+                return WellKnownError("error.not_yet_implemented", type);
+
+            return depth == 0 ? null : WellKnownError("error.no_matching_close", type, init);
+        }
+
+        private InterpreterResult? ProcessStatement(string line) => Interpreter.Telemetry.Measure(TelemetryCategory.ProcessStatement, delegate
+        {
+            InterpreterResult? result = line.Match(null, new Dictionary<Regex, Func<Match, InterpreterResult?>>
+            {
+                [REGEX_EXIT] = m =>
+                {
+                    string code = m.Groups["code"].Value;
+
+                    if (string.IsNullOrWhiteSpace(code))
+                        code = "0";
+
+                    Union<InterpreterError, Variant> result = ProcessAsVariant(code);
+
+                    if (result.Is(out Variant value))
+                    {
+                        Interpreter.Stop((int)value.ToNumber());
+
+                        return InterpreterResult.OK;
+                    }
+                    else
+                        return (InterpreterError)result;
+                },
+                [REGEX_RETURN] = m =>
+                {
+                    if (CurrentFunction.IsMainFunction)
+                        return WellKnownError("error.invalid_return");
+
+                    string optval = m.Groups["value"].Value;
+
+                    if (string.IsNullOrWhiteSpace(optval))
+                        optval = "0";
+
+                    Union<InterpreterError, Variant> result = ProcessAsVariant(optval);
+
+                    if (result.Is(out Variant value))
+                        Return(value);
+                    else
+                        return (InterpreterError)result;
+
+                    return InterpreterResult.OK;
+                },
+                [REGEX_FORTO] = m =>
+                {
+                    Union<InterpreterError, PARSABLE_EXPRESSION> start = ProcessAsRawExpression(m.Groups["start"].Value);
+                    string step = m.Groups["step"].Value is { Length: > 0 } s ? s : "1";
+
+                    if (start.Is(out InterpreterError? error))
+                        return error;
+                    else if (start.UnsafeItem is PARSABLE_EXPRESSION.AnyExpression
+                    {
+                        Item: EXPRESSION.Binary
+                        {
+                            Item:
+                            {
+                                Item1: EXPRESSION.Variable { Item: VARIABLE counter },
+                                Item2: { IsEqualCaseInsensitive: true },
+                            }
+                        }
+                    } assg)
+                    {
+                        if (ProcessAssignmentStatement(assg, false).Is(out error))
+                            return error;
+
+                        SourceLocation loc_for = CurrentLocation;
+                        int eip_for = _instruction_pointer;
+                        int depth = 1;
+
+                        while (MoveNext())
+                        {
+                            if (CurrentLineContent.Match(REGEX_NEXT, out Match _))
+                                --depth;
+                            else if (CurrentLineContent.Match(REGEX_FOR, out Match _))
+                                ++depth;
+
+                            if (depth == 0)
+                            {
+                                Variable v_first = VariableResolver.CreateTemporaryVariable();
+                                string first = '$' + v_first.Name;
+                                string stop = '$' + VariableResolver.CreateTemporaryVariable().Name;
+
+                                v_first.Value = Variant.True;
+
+                                InsertReplaceSourceCode(_instruction_pointer, $"WEnd");
+                                InsertReplaceSourceCode(eip_for,
+                                    $"While True",
+                                    $"If {first} Then",
+                                    $"{first} = False",
+                                    $"Else",
+                                    $"{stop} = Number({m.Groups["stop"]})",
+                                    $"If {counter} = {stop} Then",
+                                    $"ExitLoop",
+                                    $"EndIf",
+                                    $"{counter} += {step}",
+                                    $"EndIf"
+                                );
+                                _instruction_pointer = eip_for - 1;
+
+                                return InterpreterResult.OK;
+                            }
+                        }
+
+                        return WellKnownError("error.no_matching_close", "For", loc_for);
+                    }
+                    else
+                        return WellKnownError("error.malformed_for_expr", m.Groups["start"]);
+                },
+                [REGEX_FORIN] = m =>
+                {
+                    string counter_variables = m.Groups["variable"].Value.Trim();
+
+                    if (counter_variables.Match($"^{REGEX_VARIABLE}$", out Match _))
+                        counter_variables = $"${VariableResolver.CreateTemporaryVariable().Name}, {counter_variables}";
+
+                    if (!counter_variables.Match(REGEX_FORIN_VARIABLES, out Match m_iterator_variables))
+                        return WellKnownError("error.unparsable_iteration_variable", m.Groups["variable"]);
+
+                    Union<InterpreterError, Variable> get_or_create(string group)
+                    {
+                        if (!VariableResolver.TryGetVariable(m_iterator_variables.Groups[group].Value, VariableSearchScope.Local, out Variable? var))
+                            var = VariableResolver.CreateVariable(CurrentLocation, m_iterator_variables.Groups[group].Value, false);
+
+                        if (var.IsConst)
+                            return WellKnownError("error.constant_assignment", var.Name, var.DeclaredLocation);
+                        else
+                            return var;
+                    }
+
+                    return get_or_create("key").Match(err => err, iterator_key =>
+                        get_or_create("value").Match(err => err, iterator_value =>
+                        {
+                            SourceLocation loc_for = CurrentLocation;
+                            int eip_for = _instruction_pointer;
+                            int depth = 1;
+
+                            while (MoveNext())
+                            {
+                                if (CurrentLineContent.Match(REGEX_NEXT, out Match _))
+                                    --depth;
+                                else if (CurrentLineContent.Match(REGEX_FOR, out Match _))
+                                    ++depth;
+
+                                if (depth == 0)
+                                {
+                                    string iterator = VariableResolver.CreateTemporaryVariable().Name;
+
+                                    InsertReplaceSourceCode(_instruction_pointer,
+                                        $"WEnd",
+                                        $"{nameof(InternalsFunctionProvider.__iterator_destroy)}(\"{iterator}\")"
+                                    );
+                                    InsertReplaceSourceCode(eip_for,
+                                        $"{nameof(InternalsFunctionProvider.__iterator_create)}(\"{iterator}\", {m.Groups["expression"]})",
+                                        // TODO
+                                        // else if (!(collection = (Variant)result_coll).IsIndexable)
+                                        //     return WellKnownError("error.invalid_forin_source", collection);
+                                        $"While {nameof(InternalsFunctionProvider.__iterator_canmove)}(\"{iterator}\")",
+                                        $"${iterator_key.Name} = {nameof(InternalsFunctionProvider.__iterator_currentkey)}(\"{iterator}\")",
+                                        $"${iterator_value.Name} = {nameof(InternalsFunctionProvider.__iterator_currentvalue)}(\"{iterator}\")",
+                                        $"{nameof(InternalsFunctionProvider.__iterator_movenext)}(\"{iterator}\")"
+                                    );
+                                    _instruction_pointer = eip_for - 1;
+
+                                    return InterpreterResult.OK;
+                                }
+                            }
+
+                            return WellKnownError("error.no_matching_close", "For", loc_for);
+                        }));
+                },
+                [REGEX_WITH] = m =>
+                {
+                    Union<InterpreterError, PARSABLE_EXPRESSION> parsed = ProcessAsRawExpression(m.Groups["variable"].Value);
+
+                    if (parsed.Is(out InterpreterError? error))
+                        return error;
+                    else if (parsed.Is(out PARSABLE_EXPRESSION? pexpr) && pexpr is PARSABLE_EXPRESSION.AnyExpression
+                    {
+                        Item: EXPRESSION.Variable
+                        {
+                            Item: VARIABLE variable
+                        }
+                    } && VariableResolver.TryGetVariable(variable, VariableSearchScope.Global, out Variable? withctx) && !withctx.IsConst)
+                    {
+                        _withcontext_stack.Push(withctx);
+
+                        return InterpreterResult.OK;
+                    }
+                    else
+                        return WellKnownError("error.invalid_with_target");
+                },
+                [REGEX_ENDWITH] = _ =>
+                {
+                    if (_withcontext_stack.TryPop(out Variable _))
+                        return InterpreterResult.OK;
+                    else
+                        return WellKnownError("error.unexpected_close", line, "With");
+                },
+                [REGEX_REDIM] = m =>
+                {
+                    Union<InterpreterError, PARSABLE_EXPRESSION>? parsed = ProcessAsRawExpression(m.Groups["expression"].Value);
+
+                    if (parsed.Is(out PARSABLE_EXPRESSION? expr) && expr is PARSABLE_EXPRESSION.AnyExpression
+                    {
+                        Item: EXPRESSION.Indexer { Item: { Item1: EXPRESSION.Variable { Item: { Name: string varname } }, Item2: EXPRESSION index } }
+                    })
+                        if (VariableResolver.TryGetVariable(varname, VariableSearchScope.Global, out Variable? variable) && !variable.IsConst)
+                        {
+                            Union<InterpreterError, Variant> size = ProcessExpression(index);
+
+                            if (size.Is(out Variant size_value) && variable.Value.ResizeArray(Interpreter, (int)size_value, out Variant? new_arr) && new_arr is Variant arr)
+                            {
+                                variable.Value = arr;
+
+                                return InterpreterResult.OK;
+                            }
+
+                            return WellKnownError("error.invalid_redim_size", index);
+                        }
+                        else
+                            return WellKnownError("error.invalid_redim_expression", varname);
+
+                    return parsed.As<InterpreterError>() ?? WellKnownError("error.invalid_redim_expression", m.Groups["expression"]);
+                },
+                [REGEX_DO] = _ =>
+                {
+                    SourceLocation do_loc = CurrentLocation;
+                    int eip_do = _instruction_pointer;
+                    int depth = 1;
+
+                    while (MoveNext())
+                        if (CurrentLineContent.Match(REGEX_DO, out Match _))
+                            ++depth;
+                        else if (CurrentLineContent.Match(REGEX_UNTIL, out Match m))
+                        {
+                            --depth;
+
+                            if (depth == 0)
+                            {
+                                InsertReplaceSourceCode(_instruction_pointer, "WEnd");
+
+                                Variable temp = VariableResolver.CreateTemporaryVariable();
+                                string first = '$' + temp.Name;
+
+                                temp.Value = Variant.True;
+
+                                InsertReplaceSourceCode(eip_do,
+                                    $"While ({first} Or Not({m.Groups["expression"]}))",
+                                    $"{first} = False"
+                                );
+                                _instruction_pointer = eip_do - 1;
+
+                                return InterpreterResult.OK;
+                            }
+                        }
+
+                    return WellKnownError("error.no_matching_close", "Do", do_loc);
+                },
+                [REGEX_UNTIL] = _ => WellKnownError("error.unexpected_close", "Until", "Do"), // REGEX_UNTIL is handled by the REGEX_DO-case
+                [REGEX_WHILE] = m =>
+                {
+                    Union<InterpreterError, Variant> result = ProcessAsVariant(m.Groups["expression"].Value);
+
+                    if (result.Is(out InterpreterError? error))
+                        return error;
+
+                    if (!result.As<Variant>().ToBoolean())
+                        return MoveToEndOf(BlockStatementType.While) ?? InterpreterResult.OK;
+                    else
+                        _while_stack.Push(InsertInternalJumpLabel());
+
+                    return InterpreterResult.OK;
+                },
+                [REGEX_WEND] = _ =>
+                {
+                    _while_stack.TryPop(out string? label);
+
+                    if (label is null)
+                        return WellKnownError("error.unexpected_close", "WEnd", "While");
+                    else if (MoveTo(label) is InterpreterError error)
+                        return error;
+
+                    RemoveInternalJumpLabel(label);
+
+                    --_instruction_pointer;
+
+                    return InterpreterResult.OK;
+                },
+                [REGEX_IF] = m =>
+                {
+                    Union<InterpreterError, Variant> condition = ProcessAsVariant(m.Groups["condition"].Value);
+                    bool elif = m.Groups["elif"].Length > 0;
+
+                    if (elif)
+                        if (_if_stack.TryPop(out bool cond))
+                        {
+                            if (cond)
+                                condition = Variant.False;
+                        }
+                        else
+                            return WellKnownError("error.missing_if");
+
+                    if (condition.Is(out InterpreterError? error))
+                        return error;
+                    else
+                    {
+                        bool cond = condition.As<Variant>().ToBoolean();
+
+                        _if_stack.Push(cond);
+
+                        if (!cond && MoveToEndOf(BlockStatementType.If) is InterpreterError err)
+                            return err;
+                    }
+
+                    return InterpreterResult.OK;
+                },
+                [REGEX_ELSE] = _ =>
+                {
+                    if (_if_stack.TryPop(out bool cond))
+                    {
+                        if (cond && MoveToEndOf(BlockStatementType.If) is InterpreterError error)
+                            return error;
+                    }
+                    else
+                        return WellKnownError("error.missing_if");
+
+                    return InterpreterResult.OK;
+                },
+                [REGEX_ENDIF] = m => _if_stack.TryPop(out _) ? InterpreterResult.OK : WellKnownError("error.unexpected_close", m.Value, BlockStatementType.If),
+                [REGEX_GOTO] = m =>
+                {
+                    if (Interpreter.CommandLineOptions.StrictMode)
+                        return WellKnownError("error.experimental.goto_instructions");
+
+                    return MoveTo(m.Groups["label"].Value) ?? InterpreterResult.OK;
+                },
+                [REGEX_CONTINUELOOP_EXITLOOP] = m =>
+                {
+                    bool exit = m.Groups["mode"].Value.Equals("exit", StringComparison.InvariantCultureIgnoreCase);
+                    int level = 1;
+
+                    if (m.Groups["level"].Length > 0)
+                    {
+                        Union<InterpreterError, Variant> parsed = ProcessAsVariant(m.Groups["level"].Value);
+
+                        if (parsed.Is(out InterpreterError? error))
+                            return error;
+
+                        level = (int)(Variant)parsed;
+                    }
+
+                    while (level-- > 0)
+                    {
+                        if (!_while_stack.TryPop(out string? label))
+                            return WellKnownError("error.unexpected_contexitloop", exit ? "ExitLoop" : "ContinueLoop");
+                        else
+                        {
+                            if ((exit ? MoveToEndOf(BlockStatementType.While) : MoveTo(label)) is InterpreterError error)
+                                return error;
+                        }
+
+                        RemoveInternalJumpLabel(label);
+
+                        --_instruction_pointer;
+                    }
+
+                    return InterpreterResult.OK;
+                },
+                [REGEX_SELECT] = _ =>
+                {
+                    _switchselect_stack.Push((null, false));
+
+                    if (MoveToEndOf(BlockStatementType.Select) is InterpreterError error)
+                        return error;
+
+                    --_instruction_pointer;
+
+                    return InterpreterResult.OK;
+                },
+                [REGEX_SWITCH] = m =>
+                {
+                    Union<InterpreterError, Variant> expression = ProcessAsVariant(m.Groups["expression"].Value);
+
+                    if (expression.Is(out InterpreterError? error))
+                        return error;
+                    else
+                        _switchselect_stack.Push(((Variant)expression, false));
+
+                    error = MoveToEndOf(BlockStatementType.Switch);
+
+                    if (error is null)
+                        --_instruction_pointer;
+
+                    return error ?? InterpreterResult.OK;
+                },
+                [REGEX_ENDSELECT] = m =>
+                {
+                    if (_switchselect_stack.TryPop(out (Variant? expr, bool) topmost) && topmost.expr is null)
+                        return InterpreterResult.OK;
+                    else
+                        return WellKnownError("error.unexpected_close", m.Value, BlockStatementType.Select);
+                },
+                [REGEX_ENDSWITCH] = m =>
+                {
+                    if (_switchselect_stack.TryPop(out (Variant? expr, bool) topmost) && topmost.expr is Variant)
+                        return InterpreterResult.OK;
+                    else
+                        return WellKnownError("error.unexpected_close", m.Value, BlockStatementType.Switch);
+                },
+                [REGEX_CASE] = m =>
+                {
+                    Variant? switch_expr = null;
+
+                    if (!_switchselect_stack.TryPeek(out (Variant? switch_expr, bool handled) topmost))
+                        return WellKnownError("error.unexpected_case");
+                    else if (topmost.handled)
+                    {
+                        if (MoveToEndOf(switch_expr is null ? BlockStatementType.Select : BlockStatementType.Switch) is InterpreterError error)
+                            return error!;
+                        else
+                            --_instruction_pointer;
+
+                        return InterpreterResult.OK;
+                    }
+                    else if (REGEX_ELSE.IsMatch(m.Groups["expression"].Value))
+                        return InterpreterResult.OK;
+                    else
+                        switch_expr = topmost.switch_expr;
+
+                    Union<InterpreterError, PARSABLE_EXPRESSION> case_expr = ProcessAsRawExpression(m.Groups["expression"].Value);
+                    InterpreterResult process_success(bool success)
+                    {
+                        _switchselect_stack.TryPop(out topmost);
+                        _switchselect_stack.Push((topmost.switch_expr, success));
+
+                        if (!success)
+                            if (MoveToEndOf(BlockStatementType.Switch) is InterpreterError error)
+                                return error!;
+                            else
+                                --_instruction_pointer;
+
+                        return InterpreterResult.OK;
+                    }
+
+                    if (case_expr.Is(out PARSABLE_EXPRESSION? expression))
+                        if (expression is PARSABLE_EXPRESSION.ToExpression { Item1: EXPRESSION from, Item2: EXPRESSION to })
+                        {
+                            if (switch_expr is Variant sw)
+                                return ProcessExpression(from).Match(err => err!, from =>
+                                       ProcessExpression(to).Match(err => err!, to => process_success(from <= sw && sw <= to)));
+                            else
+                                return WellKnownError("error.invalid_case_range", expression);
+                        }
+                        else if (expression is PARSABLE_EXPRESSION.AnyExpression { Item: EXPRESSION expr })
+                            return ProcessExpression(expr).Match(err => err!, expr => process_success(switch_expr is Variant sw ? expr.EqualsCaseInsensitive(sw) : expr.ToBoolean()));
+                        else
+                            return WellKnownError("error.invalid_case_expr", expression);
+
+                    return (InterpreterError)case_expr;
+                },
+                [REGEX_CONTINUECASE] = _ =>
+                {
+                    if (!_switchselect_stack.TryPeek(out (Variant? switch_expr, bool) topmost))
+                        return WellKnownError("error.unexpected_continuecase");
+                    else if (MoveToEndOf(topmost.switch_expr is null ? BlockStatementType.Select : BlockStatementType.Switch) is InterpreterError error)
+                        return error;
+                    else if (!REGEX_CASE.IsMatch(CurrentLineContent))
+                        _switchselect_stack.TryPop(out topmost);
+
+                    return InterpreterResult.OK;
+                },
+            });
+
+            foreach (AbstractStatementProcessor? proc in Interpreter.PluginLoader.StatementProcessors)
+                if (proc is { Regex: Regex pat } sp && line.Match(pat, out Match _))
+                    result ??= sp.ProcessStatement(this, line);
+
+            return result;
+        });
+
+        private InterpreterError? ProcessExpressionStatement(string line) => Interpreter.Telemetry.Measure(TelemetryCategory.ProcessExpressionStatement, delegate
+        {
+            try
+            {
+                if (ProcessDeclarationModifiers(ref line, out DeclarationType declaration_type, out (char op, int amount)? enum_step) is { } err)
+                    return err;
+
+                ParserConstructor<PARSABLE_EXPRESSION>.ParserWrapper? provider = declaration_type is DeclarationType.None ? Interpreter.ParserProvider.ExpressionParser : Interpreter.ParserProvider.MultiDeclarationParser;
+                PARSABLE_EXPRESSION? expression = provider.Parse(line).ParsedValue;
+
+                MainProgram.PrintfDebugMessage("debug.au3thread.expr_statement", expression);
+
+                if (declaration_type == DeclarationType.None)
+                    return ProcessAssignmentStatement(expression, false).Match(Generics.id, _ => null);
+                else if (expression is PARSABLE_EXPRESSION.MultiDeclarationExpression multi_decl)
+                    return ProcessMultiDeclarationExpression(multi_decl, declaration_type, enum_step);
+                else
+                    return WellKnownError("error.invalid_multi_decl", line);
+            }
+            catch (Exception ex)
+            {
+                return Interpreter.Telemetry.Measure(TelemetryCategory.Exceptions, delegate
+                {
+                    if (Interpreter.CommandLineOptions.Verbosity > Verbosity.q)
+                        return new InterpreterError(CurrentLocation, $"{Interpreter.CurrentUILanguage["error.unparsable_line", line, ex.Message]}\n\nStack trace:\n{ex.StackTrace}");
+                    else
+                        return WellKnownError("error.unparsable_line", line, ex.Message);
+                });
+            }
+        });
+
+        private Union<InterpreterError, PARSABLE_EXPRESSION> ProcessAsRawExpression(string expression) =>
+            Interpreter.Telemetry.Measure<Union<InterpreterError, PARSABLE_EXPRESSION>>(TelemetryCategory.ProcessExpression, delegate
+            {
+                try
+                {
+                    ParserConstructor<PARSABLE_EXPRESSION>.ParserWrapper? provider = Interpreter.ParserProvider.ExpressionParser;
+                    PARSABLE_EXPRESSION parsed = provider.Parse(expression).ParsedValue;
+
+                    MainProgram.PrintfDebugMessage("debug.au3thread.raw_expr", parsed);
+
+                    return parsed;
+                }
+                catch (Exception ex)
+                {
+                    return Interpreter.Telemetry.Measure(TelemetryCategory.Exceptions, () => WellKnownError("error.unparsable_line", expression, ex.Message));
+                }
+            });
+
+        internal Union<InterpreterError, Variant> ProcessAsVariant(string expression)
+        {
+            Union<InterpreterError, PARSABLE_EXPRESSION>? result = ProcessAsRawExpression(expression);
+
+            if (result.Is(out PARSABLE_EXPRESSION.AnyExpression? any))
+            {
+                EXPRESSION folded = Interpreter.Telemetry.Measure(TelemetryCategory.ExpressionCleanup, () => Cleanup.FoldConstants(any.Item));
+
+                return ProcessExpression(folded);
+            }
+            else
+                return (InterpreterError?)result ?? WellKnownError("error.unparsable_line", expression);
+        }
+
+        private InterpreterError? ProcessDeclarationModifiers(ref string line, out DeclarationType declaration_type, out (char op, int amount)? enum_step)
+        {
+            declaration_type = DeclarationType.None;
+            enum_step = null;
+
+            while (line.Match(REGEX_DECLARATION_MODIFIER, out Match m_modifier))
+            {
+                DeclarationType modifier = (DeclarationType)Enum.Parse(typeof(DeclarationType), m_modifier.Value, true);
+
+                if (declaration_type.HasFlag(modifier))
+                    return WellKnownError("error.duplicate_modifier", modifier);
+
+                if (modifier is DeclarationType.Step)
+                    if (line.Match(REGEX_ENUM_STEP, out Match m_step))
+                    {
+                        char op = '+';
+                        int amount = int.Parse(m_step.Groups["step"].Value);
+
+                        if (m_step.Groups["op"] is { Length: > 0, Value: string s })
+                            op = s[0];
+
+                        enum_step = (op, amount);
+                    }
+                    else
+                        return WellKnownError("error.invalid_step", new string(line.TakeWhile(c => !char.IsWhiteSpace(c)).ToArray()));
+
+                declaration_type |= modifier;
+                line = line[m_modifier.Length..].TrimStart();
+            }
+
+            if (declaration_type.HasFlag(DeclarationType.Step) && !declaration_type.HasFlag(DeclarationType.Enum))
+                return WellKnownError("error.unexpected_step");
+
+            foreach ((DeclarationType m1, DeclarationType m2) in new[]
+            {
+                (DeclarationType.Dim, DeclarationType.Global),
+                (DeclarationType.Dim, DeclarationType.Local),
+                (DeclarationType.Dim, DeclarationType.Static),
+                (DeclarationType.Enum, DeclarationType.Static),
+                (DeclarationType.Local, DeclarationType.Global),
+                (DeclarationType.Static, DeclarationType.Const),
+            })
+                if (declaration_type.HasFlag(m1) && declaration_type.HasFlag(m2))
+                    return WellKnownError("error.incomplatible_modifiers", m1, m2);
+
+            return null;
+        }
+
+        private InterpreterError? ProcessMultiDeclarationExpression(PARSABLE_EXPRESSION.MultiDeclarationExpression multi_decl, DeclarationType decltype, (char op, int amount)? enum_step) =>
+            Interpreter.Telemetry.Measure(TelemetryCategory.ProcessDeclaration, delegate
+            {
+                InterpreterError? error = null;
+                Variable? variable;
+
+                foreach ((VARIABLE variable_ast, VARIABLE_DECLARATION declaration) in multi_decl.Item.Select(t => t.ToValueTuple()))
+                {
+                    error ??= ProcessVariableDeclaration(variable_ast, decltype);
+
+                    switch (declaration)
+                    {
+                        case VARIABLE_DECLARATION.Scalar { Item: null }:
+                            if (decltype.HasFlag(DeclarationType.Const))
+                                return WellKnownError("error.uninitialized_constant", variable_ast);
+                            else
+                                break;
+                        case VARIABLE_DECLARATION.Scalar { Item: FSharpOption<EXPRESSION> { Value: EXPRESSION expression } }:
+                            {
+                                // TODO : enum step handling
+
+                                var assg_expr = (ASSIGNMENT_TARGET.NewVariableAssignment(variable_ast), OPERATOR_ASSIGNMENT.Assign, expression).ToTuple();
+                                Union<InterpreterError, Variant> result = ProcessAssignmentStatement(PARSABLE_EXPRESSION.NewAssignmentExpression(assg_expr), true);
+
+                                if (result.Is(out Variant value))
+                                    MainProgram.PrintDebugMessage($"{variable_ast} = {value}");
+                                else
+                                    error ??= (InterpreterError)result;
+                            }
+                            break;
+                        case VARIABLE_DECLARATION.Array { Item1: int size, Item2: FSharpList<EXPRESSION> items }:
+                            if (size < 0)
+                                return WellKnownError("error.invalid_array_size", variable_ast, size);
+                            else if (items.Length > size)
+                                return WellKnownError("error.too_many_array_items", variable_ast, size, items.Length);
+                            else if (VariableResolver.TryGetVariable(variable_ast, VariableSearchScope.Global, out variable))
+                            {
+                                variable.Value = Variant.NewArray(size);
+
+                                int index = 0;
+
+                                foreach (EXPRESSION item in items)
+                                {
+                                    Union<InterpreterError, Variant> result = ProcessExpression(item);
+
+                                    if (result.Is(out error))
+                                        return error;
+
+                                    variable.Value.TrySetIndexed(Interpreter, index, result);
+                                    ++index;
+                                }
+
+                                break;
+                            }
+                            else
+                                return WellKnownError("error.undeclared_variable", variable_ast);
+                        case VARIABLE_DECLARATION.Map:
+                            if (VariableResolver.TryGetVariable(variable_ast, VariableSearchScope.Global, out variable))
+                            {
+                                variable.Value = Variant.NewMap();
+
+                                break;
+                            }
+                            else
+                                return WellKnownError("error.undeclared_variable", variable_ast);
+                        default:
+                            return WellKnownError("error.not_yet_implemented", declaration);
+                    }
+                }
+
+                return error;
+            });
+
+        private InterpreterError? ProcessVariableDeclaration(VARIABLE variable, DeclarationType decltype)
+        {
+            bool constant = decltype.HasFlag(DeclarationType.Const) || decltype.HasFlag(DeclarationType.Enum);
+            bool global = decltype.HasFlag(DeclarationType.Global) && !decltype.HasFlag(DeclarationType.Local);
+
+            if (decltype.HasFlag(DeclarationType.Static) && !global)
+                return WellKnownError("error.not_yet_implemented", "static"); // TODO : static
+
+            VariableScope scope = (global ? VariableResolver.GlobalRoot : null) ?? VariableResolver;
+
+            // if (decltype.HasFlag(DeclarationType.Dim) || decltype == DeclarationType.None)
+            //     global = CurrentFunction.IsMainFunction;
+
+            if (scope.TryGetVariable(variable, VariableSearchScope.Global, out Variable? var))
+            {
+                if (!(var.IsGlobal && decltype.HasFlag(DeclarationType.Local))) // potential conflict
+                    if (constant && !var.IsConst)
+                        return WellKnownError("error.cannot_make_constant", var, var.DeclaredLocation);
+                    else if (var.IsConst)
+                        return WellKnownError("error.redefining_constant", var, var.DeclaredLocation);
+            }
+
+            scope.CreateVariable(CurrentLocation, variable, constant);
+
+            return null;
+        }
+
+        private Union<InterpreterError, Variant> ProcessAssignmentStatement(PARSABLE_EXPRESSION assignment, bool force) =>
+            Interpreter.Telemetry.Measure<Union<InterpreterError, Variant>>(TelemetryCategory.ProcessAssignment, delegate
+            {
+                (ASSIGNMENT_TARGET target, EXPRESSION expression) = Interpreter.Telemetry.Measure(TelemetryCategory.ExpressionCleanup, () => Cleanup.CleanUpExpression(assignment));
+
+                switch (target)
+                {
+                    case ASSIGNMENT_TARGET.VariableAssignment { Item: VARIABLE variable }:
+                        {
+                            if (VariableResolver.TryGetVariable(variable.Name, VariableSearchScope.Global, out Variable? target_variable))
+                            {
+                                if (target_variable.IsConst && !force)
+                                    return WellKnownError("error.constant_assignment", target_variable, target_variable.DeclaredLocation);
+                            }
+                            else
+                                target_variable = VariableResolver.CreateVariable(CurrentLocation, variable.Name, false);
+
+                            if (target_variable is null)
+                                return WellKnownError("error.invalid_assignment_target", target);
+                            else
+                                return ProcessVariableAssignment(target_variable, expression);
+                        }
+                    case ASSIGNMENT_TARGET.IndexedAssignment { Item: { } indexer }:
+                        return ProcessExpression(indexer.Item1).Match<Union<InterpreterError, Variant>>(err => err, target =>
+                               ProcessExpression(indexer.Item2).Match<Union<InterpreterError, Variant>>(err => err, key =>
+                               ProcessExpression(expression).Match<Union<InterpreterError, Variant>>(err => err, value =>
+                               {
+                                   if (target.TrySetIndexed(Interpreter, key, value))
+                                       return value;
+
+                                   return WellKnownError("error.invalid_index_assg", target.AssignedTo, key);
+                               })));
+                    case ASSIGNMENT_TARGET.MemberAssignemnt { Item: MEMBER_EXPRESSION.ExplicitMemberAccess { Item1: { } targ, Item2: { Item: string memb } } }:
+                        return ProcessExpression(targ).Match<Union<InterpreterError, Variant>>(err => err, target =>
+                               ProcessExpression(expression).Match<Union<InterpreterError, Variant>>(err => err, value =>
+                               {
+                                   if (target.TrySetMember(Interpreter, memb, value) || target.TrySetIndexed(Interpreter, memb, value))
+                                       return value;
+
+                                   return WellKnownError("error.invalid_index_assg", target.AssignedTo, memb);
+                               }));
+                    case ASSIGNMENT_TARGET.MemberAssignemnt { Item: MEMBER_EXPRESSION.ImplicitMemberAccess { Item: { Item: string member } } }:
+                        {
+                            if (_withcontext_stack.TryPeek(out Variable? variable))
+                                return ProcessExpression(expression).Match<Union<InterpreterError, Variant>>(err => err, value =>
+                                {
+                                    if (variable.Value.TrySetMember(Interpreter, member, value) || variable.Value.TrySetIndexed(Interpreter, member, value))
+                                        return value;
+
+                                    return WellKnownError("error.invalid_index_assg", variable, member);
+                                });
+                            else
+                                return WellKnownError("error.invalid_with_access", member);
+                        }
+                    default:
+                        return WellKnownError("error.invalid_assignment_target", target);
+                }
+            });
+
+        private Union<InterpreterError, Variant> ProcessVariableAssignment(Variable variable, EXPRESSION expression)
+        {
+            foreach (VARIABLE v in expression.ReferencedVariables)
+                if (!VariableResolver.HasVariable(v, VariableSearchScope.Global))
+                    return WellKnownError("error.undeclared_variable", v);
+
+            Union<InterpreterError, Variant> value = ProcessExpression(expression);
+
+            if (value.Is(out Variant variant))
+                (variable.ReferencedVariable ?? variable).Value = variant;
+
+            return value;
+        }
+
+        private Union<InterpreterError, Variant> ProcessExpression(EXPRESSION? expression) =>
+            Interpreter.Telemetry.Measure(TelemetryCategory.EvaluateExpression, delegate
+            {
+                Union<InterpreterError, Variant> value = expression switch
+                {
+                    null => Variant.Null,
+                    EXPRESSION.Literal { Item: LITERAL literal } => ProcessLiteral(literal),
+                    EXPRESSION.Variable { Item: VARIABLE variable } => ProcessVariable(variable),
+                    EXPRESSION.Macro { Item: MACRO macro } => ProcessMacro(macro),
+                    EXPRESSION.FunctionName { Item: { Item: string func_name } } =>
+                        Interpreter.ScriptScanner.TryResolveFunction(func_name) is ScriptFunction func
+                        ? (Union<InterpreterError, Variant>)Variant.FromFunction(func)
+                        : (Union<InterpreterError, Variant>)WellKnownError("error.unresolved_func", func_name),
+                    EXPRESSION.Unary { Item: Tuple<OPERATOR_UNARY, EXPRESSION> unary } => ProcessUnary(unary.Item1, unary.Item2),
+                    EXPRESSION.Binary { Item: Tuple<EXPRESSION, OPERATOR_BINARY, EXPRESSION> binary } => ProcessBinary(binary.Item1, binary.Item2, binary.Item3),
+                    EXPRESSION.Ternary { Item: Tuple<EXPRESSION, EXPRESSION, EXPRESSION> ternary } => ProcessTernary(ternary.Item1, ternary.Item2, ternary.Item3),
+                    EXPRESSION.Member { Item: MEMBER_EXPRESSION member } => ProcessMember(member),
+                    EXPRESSION.Indexer { Item: Tuple<EXPRESSION, EXPRESSION> indexer } => ProcessIndexer(indexer.Item1, indexer.Item2),
+                    EXPRESSION.FunctionCall { Item: FUNCCALL_EXPRESSION funccall } => ProcessFunctionCall(funccall),
+                    _ => WellKnownError("error.not_yet_implemented", expression),
+                };
+
+                if (value.Is(out Variant v))
+                    MainProgram.PrintfDebugMessage("debug.au3thread.expression", expression, v.ToDebugString(Interpreter));
+
+                return value;
+            });
+
+        private Union<InterpreterError, Variant> ProcessIndexer(EXPRESSION expr, EXPRESSION index) =>
+            ProcessExpression(expr).Match<Union<InterpreterError, Variant>>(err => err, @object =>
+            ProcessExpression(index).Match<Union<InterpreterError, Variant>>(err => err, key =>
+            {
+                if (@object.TryGetIndexed(Interpreter, key, out Variant value))
+                    return value;
+
+                return WellKnownError("error.invalid_index", key);
+            }));
+
+        private Union<InterpreterError, Variant> ProcessMember(MEMBER_EXPRESSION expr)
+        {
+            Union<InterpreterError, Variant> result = WellKnownError("error.not_yet_implemented", expr);
+            string? member = null;
+
+            switch (expr)
+            {
+                case MEMBER_EXPRESSION.ExplicitMemberAccess { Item1: { } objexpr, Item2: { Item: string m } }:
+                    result = ProcessExpression(objexpr);
+                    member = m;
+
+                    break;
+                case MEMBER_EXPRESSION.ImplicitMemberAccess { Item: { Item: string m } }:
+                    if (_withcontext_stack.TryPeek(out Variable? variable))
+                    {
+                        result = variable.Value;
+                        member = m;
+
+                        break;
+                    }
+                    else
+                        return WellKnownError("error.invalid_with_access", m);
+            }
+
+            if (result.Is(out Variant value) && member is string)
+            {
+                if (value.TryGetMember(Interpreter, member, out Variant v))
+                    result = v;
+                else if (value.TryGetIndexed(Interpreter, member, out v))
+                    result = v;
+                else if (member.Equals("length", StringComparison.InvariantCultureIgnoreCase))
+                    result = (Variant)value.Length;
+                else
+                    return WellKnownError("error.unknown_member", member);
+            }
+            
+            return result;
+        }
+
+        private Union<InterpreterError, Variant> ProcessUnary(OPERATOR_UNARY op, EXPRESSION expr)
+        {
+            Union<InterpreterError, Variant> result = ProcessExpression(expr);
+
+            if (result.Is(out Variant value))
+                if (op.IsIdentity)
+                    result = +value;
+                else if (op.IsNegate)
+                    result = -value;
+                else if (op.IsNot)
+                    result = !value;
+                else if (op is OPERATOR_UNARY.Cast { Item: { } cop })
+                    if (cop.IsCBool)
+                        result = (Variant)value.ToBoolean();
+                    else if (cop.IsCInt)
+                        result = (Variant)(int)value.ToNumber();
+                    else if (cop.IsCNumber)
+                        result = (Variant)value.ToNumber();
+                    else if (cop.IsCString)
+                        result = (Variant)value.ToString();
+                    else if (cop.IsCBinary)
+                        result = (Variant)value.ToBinary();
+                    else
+                        result = WellKnownError("error.unsupported_operator", cop);
+                else
+                    result = WellKnownError("error.unsupported_operator", op);
+
+            return result;
+        }
+
+        private Union<InterpreterError, Variant> ProcessBinary(EXPRESSION expr1, OPERATOR_BINARY op, EXPRESSION expr2)
+        {
+            InterpreterError? evaluate(EXPRESSION expr, out Variant target)
+            {
+                Union<InterpreterError, Variant> result = ProcessExpression(expr);
+
+                target = Variant.Zero;
+
+                if (result.Is(out InterpreterError? error))
+                    return error;
+
+                target = (Variant)result;
+
+                return null;
+            }
+
+            InterpreterError? err = evaluate(expr1, out Variant e1);
+            Variant e2;
+
+            if (err is { })
+                return err;
+            else if (op.IsAnd)
+            {
+                if (!e1.ToBoolean())
+                    return Variant.False;
+                else if ((err = evaluate(expr2, out e2)) is { })
+                    return err;
+                else
+                    return e2;
+            }
+            else if (op.IsOr)
+            {
+                if (e1.ToBoolean())
+                    return Variant.True;
+                else if ((err = evaluate(expr2, out e2)) is { })
+                    return err;
+                else
+                    return e2;
+            }
+            else
+                err = evaluate(expr2, out e2);
+
+            if (err is { })
+                return err;
+            else if (op.IsStringConcat)
+                return e1 & e2;
+            else if (op.IsEqualCaseSensitive)
+                return Variant.FromBoolean(e1.EqualsCaseSensitive(e2));
+            else if (op.IsEqualCaseInsensitive)
+                return Variant.FromBoolean(e1.EqualsCaseInsensitive(e2));
+            else if (op.IsUnequal)
+                return Variant.FromBoolean(e1.NotEquals(e2));
+            else if (op.IsGreater)
+                return Variant.FromBoolean(e1 > e2);
+            else if (op.IsGreaterEqual)
+                return Variant.FromBoolean(e1 >= e2);
+            else if (op.IsLower)
+                return Variant.FromBoolean(e1 < e2);
+            else if (op.IsLowerEqual)
+                return Variant.FromBoolean(e1 <= e2);
+            else if (op.IsAdd)
+                return e1 + e2;
+            else if (op.IsSubtract)
+                return e1 - e2;
+            else if (op.IsMultiply)
+                return e1 * e2;
+            else if (op.IsDivide)
+                return e1 / e2;
+            else if (op.IsPower)
+                return e1 ^ e2;
+
+            // TODO : modulus
+
+            return WellKnownError("error.unsupported_operator", op);
+        }
+
+        private Union<InterpreterError, Variant> ProcessTernary(EXPRESSION expr1, EXPRESSION expr2, EXPRESSION expr3) =>
+            ProcessExpression(expr1).Match<Union<InterpreterError, Variant>>(e => e, cond => ProcessExpression(cond.ToBoolean() ? expr2 : expr3));
+
+        private Union<InterpreterError, Variant> ProcessFunctionCall(FUNCCALL_EXPRESSION funccall)
+        {
+            Union<Variant[], InterpreterError> ProcessRawArguments(FSharpList<EXPRESSION> raw_args)
+            {
+                Variant[] arguments = new Variant[raw_args.Length];
+                int i = 0;
+
+                foreach (EXPRESSION arg in raw_args)
+                {
+                    Union<InterpreterError, Variant>? res = ProcessExpression(arg);
+
+                    if (res.Is(out Variant value))
+                        arguments[i++] = value;
+                    else
+                        return (InterpreterError)res;
+                }
+
+                return arguments;
+            }
+
+            switch (funccall)
+            {
+                case FUNCCALL_EXPRESSION.DirectFunctionCall { Item1: { Item: string func_name }, Item2: var raw_args }:
+                    if (Interpreter.ScriptScanner.TryResolveFunction(func_name) is ScriptFunction func)
+                        return ProcessRawArguments(raw_args).Match<Union<InterpreterError, Variant>>(args => Call(func, args), err => err);
+                    else
+                        return WellKnownError("error.unresolved_func", func_name);
+                case FUNCCALL_EXPRESSION.MemberCall member_call:
+                    throw new NotImplementedException();
+            }
+
+            return WellKnownError("error.not_yet_implemented", funccall);
+        }
+
+        private Union<InterpreterError, Variant> ProcessMacro(MACRO macro)
+        {
+            string name = macro.Name;
+
+            foreach (AbstractMacroProvider provider in Interpreter.PluginLoader.MacroProviders)
+                if (provider.ProvideMacroValue(this, name, out Variant? value) && value.HasValue)
+                    return value.Value;
+
+            return WellKnownError("error.unknown_macro", macro.Name);
+        }
+
+        private Union<InterpreterError, Variant> ProcessVariable(VARIABLE variable)
+        {
+            if (variable == VARIABLE.Discard)
+                return WellKnownError("error.invalid_discard_access", VARIABLE.Discard, FrameworkMacros.MACRO_DISCARD);
+
+            if (VariableResolver.TryGetVariable(variable, VariableSearchScope.Global, out Variable? var))
+            {
+                Variant value = var.Value;
+
+                if (value.AssignedTo != var)
+                    var.Value = value.AssignTo(var); // update parent var
+
+                return value;
+            }
+            else
+                return WellKnownError("error.undeclared_variable", variable);
+        }
+
+        private Variant ProcessLiteral(LITERAL literal) => Variant.FromLiteral(literal); // TODO : on error throw ?
+
+        private InterpreterResult? UseExternalLineProcessors(string line)
+        {
+            foreach (AbstractLineProcessor proc in Interpreter.PluginLoader.LineProcessors)
+                if (proc.CanProcessLine(line) && Interpreter.Telemetry.Measure(TelemetryCategory.ExternalProcessor, () => proc.ProcessLine(this, line)) is { } res)
+                    return res;
+
+            return null;
+        }
+
+        private InterpreterError WellKnownError(string key, params object?[] args) => InterpreterError.WellKnown(CurrentLocation, key, args);
+    }
+
+    [Flags]
+    public enum DeclarationType
+        : byte
+    {
+        None = 0b_0000_0000,
+        Dim = 0b_0000_0001,
+        Local = 0b_0000_0010,
+        Global = 0b_0000_0100,
+        Const = 0b_0000_1000,
+        Static = 0b_0001_0000,
+        Enum = 0b_0010_0000,
+        Step = 0b_0100_0000,
+    }
+
+    public enum BlockStatementType
+        : int
+    {
+        __function__ = default,
+        While,
+        If,
+        Select,
+        Switch,
+        // Case,
+    }
+}
diff --git a/new/AutoItInterpreter/Runtime/Interpreter.cs b/new/AutoItInterpreter/Runtime/Interpreter.cs
index e5063732..dfd34344 100644
--- a/new/AutoItInterpreter/Runtime/Interpreter.cs
+++ b/new/AutoItInterpreter/Runtime/Interpreter.cs
@@ -1,5 +1,4 @@
-using System.Collections.Concurrent;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Linq;
 using System;
 
@@ -17,7 +16,11 @@ namespace Unknown6656.AutoIt3.Runtime
 {
     using static AST;
 
-
+    /// <summary>
+    /// Represents the core management logic of the AutoIt interpreter.
+    /// <br/>
+    /// The interpreter consists of threads, the global object storage, service connector, telemetry parser, the plugin loading system etc.
+    /// </summary>
     public sealed class Interpreter
         : IDisposable
         , IDebugPrintingService
@@ -29,22 +32,47 @@ public sealed class Interpreter
         private volatile int _error;
 
 
-        internal static Interpreter[] Instances => _instances.ToArray();
+        /// <summary>
+        /// <b>[UNSAFE!]</b>
+        /// Returns a collection of currently active interpreter instances.
+        /// </summary>
+        public static Interpreter[] ActiveInstances => _instances.ToArray();
 
+        /// <summary>
+        /// The interpreter's random number generator. The used generator can be reset and seeded using the methods <see cref="ResetRandom"/> and <see cref="ResetRandom(int)"/>.
+        /// </summary>
         public Random Random { get; private set; }
 
+        /// <summary>
+        /// The interpreter's main thread.
+        /// </summary>
         public AU3Thread? MainThread { get; private set; }
 
+        /// <summary>
+        /// A collection of currently active threads.
+        /// </summary>
         public AU3Thread[] Threads => _threads.ToArray();
 
+        /// <summary>
+        /// The interpreter's <i>global</i> <see cref="VariableScope"/>. This scope contains all global variables.
+        /// </summary>
         public VariableScope VariableResolver { get; }
 
+        /// <summary>
+        /// The command line options used to launch this interpreter.
+        /// </summary>
         public CommandLineOptions CommandLineOptions { get; }
 
+        /// <summary>
+        /// The interpreter's global object storage.
+        /// </summary>
         public GlobalObjectStorage GlobalObjectStorage { get; }
 
         public COMConnector? COMConnector { get; }
 
+        /// <summary>
+        /// Indicates whether COM interoperability is available to the interpreter.
+        /// </summary>
         public bool IsCOMAvailable => COMConnector is { };
 
         //public WinAPIConnector? Win32APIConnector { get; }
@@ -53,12 +81,18 @@ public sealed class Interpreter
 
         //public bool IsWin32APIAvailable => Win32APIConnector is { };
 
+        /// <summary>
+        /// The interpreter's script scanner and caching unit.
+        /// </summary>
         public ScriptScanner ScriptScanner { get; }
 
         public PluginLoader PluginLoader { get; }
 
         public ParserProvider ParserProvider { get; }
 
+        /// <summary>
+        /// The interpreter's telemetry logger.
+        /// </summary>
         public Telemetry Telemetry { get; }
 
         public LanguageLoader LanguageLoader { get; }
@@ -76,11 +110,22 @@ public int ErrorCode
         public Variant ExtendedValue { get; set; }
 
 
+        /// <summary>
+        /// Creates a new interpreter instance using the given command line options and language pack loader.
+        /// </summary>
+        /// <param name="opt">Command line options to initialize the interpreter.</param>
+        /// <param name="lang_loader">Language pack loader instance.</param>
         public Interpreter(CommandLineOptions opt, LanguageLoader lang_loader)
             : this(opt, new Telemetry(), lang_loader)
         {
         }
 
+        /// <summary>
+        /// Creates a new interpreter instance using the given command line options, telemetry logger, and language pack loader.
+        /// </summary>
+        /// <param name="opt">Command line options to initialize the interpreter.</param>
+        /// <param name="telemetry">Existing telemetry logger instance.</param>
+        /// <param name="lang_loader">Language pack loader instance.</param>
         public Interpreter(CommandLineOptions opt, Telemetry telemetry, LanguageLoader lang_loader)
         {
             _instances.Add(this);
@@ -119,14 +164,22 @@ public Interpreter(CommandLineOptions opt, Telemetry telemetry, LanguageLoader l
             ResetRandom();
         }
 
+        /// <summary>
+        /// Resets the random number generator (<see cref="Random"/>) to a new non-deterministic seed.
+        /// </summary>
         public void ResetRandom() => ResetRandom(Guid.NewGuid().GetHashCode());
 
+        /// <summary>
+        /// Resets the random number generator (<see cref="Random"/>) to the given seed.
+        /// </summary>
+        /// <param name="seed">New seed</param>
         public void ResetRandom(int seed)
         {
             lock (_main_thread_mutex)
                 Random = new XorShift(seed); // BuiltinRandom
         }
 
+        /// <inheritdoc/>
         public void Dispose()
         {
             foreach (AU3Thread thread in Threads)
@@ -144,24 +197,19 @@ public void Dispose()
             _instances.Remove(this);
         }
 
+        /// <inheritdoc/>
+        public override string ToString() => $"[{_threads.Count} Threads] {CommandLineOptions}";
+
+        /// <summary>
+        /// Halts the interpreter and all currently running threads with the given exit code.
+        /// </summary>
+        /// <param name="exitcode">Exit code.</param>
         public void Stop(int exitcode)
         {
             foreach (AU3Thread thread in Threads)
                 thread.Stop(exitcode);
         }
 
-        public void AddFolderToEnvPath(string dir)
-        {
-            char separator = NativeInterop.DoPlatformDependent(';', ':');
-            List<string> path = Environment.GetEnvironmentVariable("PATH", EnvironmentVariableTarget.Process)?
-                                           .Split(separator, StringSplitOptions.RemoveEmptyEntries)
-                                           .ToList() ?? new();
-
-            path.Add(dir);
-
-            Environment.SetEnvironmentVariable("PATH", string.Join(separator, path.Distinct()), EnvironmentVariableTarget.Process);
-        }
-
         public AU3Thread CreateNewThread() => new AU3Thread(this);
 
         internal void AddThread(AU3Thread thread) => _threads.Add(thread);
@@ -172,8 +220,22 @@ public void AddFolderToEnvPath(string dir)
 
         public void Print(CallFrame current_frame, object? value) => MainProgram.PrintScriptMessage(current_frame.CurrentThread.CurrentLocation?.FullFileName, value?.ToString() ?? "");
 
+        /// <inheritdoc/>
         void IDebugPrintingService.Print(string channel, string message) => MainProgram.PrintChannelMessage(channel, message);
 
+        /// <summary>
+        /// Runs the global function of the script file, with which the interpreter has been initialized
+        /// (This essentially executes the script stored in <see cref="CommandLineOptions.FilePath"/> of the interpreter's <see cref="CommandLineOptions"/>-property),
+        /// </summary>
+        /// <returns>The interpreter result of the script invocation.</returns>
+        public InterpreterResult Run() => CommandLineOptions.FilePath is string s ? Run(s) : new InterpreterResult(-1, InterpreterError.WellKnown(null, "error.unresolved_script", "<null>"));
+
+        /// <summary>
+        /// Creates a new (anonymous) interpreter, which invokes the given function with the given arguments.
+        /// </summary>
+        /// <param name="entry_point">The function (entry point) to be invoked.</param>
+        /// <param name="args">Arguments to be passed to the invoked function.</param>
+        /// <returns>The interpreter result of the function invocation.</returns>
         public InterpreterResult Run(ScriptFunction entry_point, Variant[] args)
         {
             try
@@ -196,11 +258,19 @@ public InterpreterResult Run(ScriptFunction entry_point, Variant[] args)
             }
         }
 
+        /// <summary>
+        /// Creates a new (anonymous) interpreter, which invokes the global function of the given script. This essentially executes the given script.
+        /// </summary>
+        /// <param name="script">The script to be executed.</param>
+        /// <returns>The interpreter result of the script invocation.</returns>
         public InterpreterResult Run(ScannedScript script) => Run(script.MainFunction, Array.Empty<Variant>());
 
+        /// <summary>
+        /// Creates a new (anonymous) interpreter, which invokes the global function of the given script. This essentially executes the given script.
+        /// </summary>
+        /// <param name="path">The path of the script to be executed.</param>
+        /// <returns>The interpreter result of the script invocation.</returns>
         public InterpreterResult Run(string path) => ScriptScanner.ScanScriptFile(SourceLocation.Unknown, path, false).Match(err => new InterpreterResult(-1, err), Run);
-
-        public InterpreterResult Run() => CommandLineOptions.FilePath is string s ? Run(s) : new InterpreterResult(-1, InterpreterError.WellKnown(null, "error.unresolved_script", "<null>"));
     }
 
     public sealed class InterpreterResult
diff --git a/new/AutoItInterpreter/Runtime/NativeInterop.cs b/new/AutoItInterpreter/Runtime/NativeInterop.cs
index e6ad8c4b..85f26dea 100644
--- a/new/AutoItInterpreter/Runtime/NativeInterop.cs
+++ b/new/AutoItInterpreter/Runtime/NativeInterop.cs
@@ -1,14 +1,17 @@
 using System.Runtime.InteropServices.ComTypes;
 using System.Runtime.InteropServices;
+using System.Collections.Generic;
 using System.Threading.Tasks;
 using System.Diagnostics;
 using System.Linq;
-using System;
 using System.Text;
-using System.Runtime.CompilerServices;
+using System;
 
 namespace Unknown6656.AutoIt3.Runtime.Native
 {
+    /// <summary>
+    /// A static module containing functions and constants for native interop.
+    /// </summary>
     public static class NativeInterop
     {
         public const uint TOKEN_READ = 0x00020008;
@@ -149,6 +152,18 @@ public static class NativeInterop
         public static extern bool SetSuspendState(bool hiberate, bool forceCritical, bool disableWakeEvent);
 
 
+        public static void AddFolderToEnvPath(string dir)
+        {
+            char separator = NativeInterop.DoPlatformDependent(';', ':');
+            List<string> path = Environment.GetEnvironmentVariable("PATH", EnvironmentVariableTarget.Process)?
+                                           .Split(separator, StringSplitOptions.RemoveEmptyEntries)
+                                           .ToList() ?? new();
+
+            path.Add(dir);
+
+            Environment.SetEnvironmentVariable("PATH", string.Join(separator, path.Distinct()), EnvironmentVariableTarget.Process);
+        }
+
         public static (string stdout, int code) Bash(string command) => DoPlatformDependent(
             delegate
             {
diff --git a/new/AutoItInterpreter/Runtime/ScriptScanner.cs b/new/AutoItInterpreter/Runtime/ScriptScanner.cs
index a7734cae..9bf1db0d 100644
--- a/new/AutoItInterpreter/Runtime/ScriptScanner.cs
+++ b/new/AutoItInterpreter/Runtime/ScriptScanner.cs
@@ -11,13 +11,14 @@
 using Unknown6656.AutoIt3.Extensibility;
 using Unknown6656.Common;
 using Unknown6656.IO;
+using Unknown6656.AutoIt3.Runtime.Native;
 
 namespace Unknown6656.AutoIt3.Runtime
 {
     using static AST;
 
     /// <summary>
-    /// Represents an AutoIt3 script scanning module.
+    /// Represents an AutoIt3 script scanning and caching module.
     /// </summary>
     public sealed class ScriptScanner
     {
@@ -292,7 +293,7 @@ private Union<InterpreterError, ScannedScript> ProcessScriptFile(FileInfo file,
                     _cached_scripts.TryAdd(script.GetHashCode(), script);
 
                     if (file.Directory is { Exists: true, FullName: string dir })
-                        Interpreter.AddFolderToEnvPath(Path.GetFullPath(dir));
+                        NativeInterop.AddFolderToEnvPath(Path.GetFullPath(dir));
                 }
 
                 return script;
diff --git a/new/AutoItInterpreter/Runtime/Variable.cs b/new/AutoItInterpreter/Runtime/Variable.cs
index 4dd155fe..c81a7dcb 100644
--- a/new/AutoItInterpreter/Runtime/Variable.cs
+++ b/new/AutoItInterpreter/Runtime/Variable.cs
@@ -326,7 +326,7 @@ public readonly bool EqualsCaseInsensitive(Variant other)
             _ => "",
         };
 
-        private readonly string ToDebugStringPrivate() => ToDebugString(Interpreter.Instances.First());
+        private readonly string ToDebugStringPrivate() => ToDebugString(Interpreter.ActiveInstances.First());
 
         public readonly string ToDebugString(Interpreter interpreter)
         {
diff --git a/new/AutoItInterpreter/version.txt b/new/AutoItInterpreter/version.txt
index 4db0ff6c..07eeab0d 100644
--- a/new/AutoItInterpreter/version.txt
+++ b/new/AutoItInterpreter/version.txt
@@ -1,2 +1,2 @@
-0.6.1256.7328
-cdfd24e8c9341f9fc41540bef89d37e540605174
\ No newline at end of file
+0.6.1257.7329
+f3c8f7753e53011c5fac5224b49c3724c68f2759
\ No newline at end of file