implemented EVAR

Author: FalsePattern

src/main/java/com/falsepattern/jfunge/interpreter/ExecutionContext.java

@@ -41,6 +41,8 @@ public interface ExecutionContext {
 
     Map<String, String> env();
 
+    List<String> envKeys();
+
     int input(boolean stagger);
 
     OutputStream output();

src/main/java/com/falsepattern/jfunge/interpreter/Interpreter.java

@@ -28,6 +28,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.TreeMap;
 
 @Accessors(fluent = true)
 public class Interpreter implements ExecutionContext {
@@ -77,6 +78,9 @@ public boolean writeFile(String file, byte[] data) throws IOException {
     @Getter
     private final Map<String, String> env;
 
+    @Getter
+    private final List<String> envKeys;
+
     private final TIntObjectMap<Map<String, Object>> globals = new TIntObjectHashMap<>();
 
     private Integer exitCode = null;
@@ -140,6 +144,8 @@ public Interpreter(String[] args, InputStream input, OutputStream output, FileIO
             this.env = new HashMap<>();
         }
         this.env.put("JFUNGE_ENV", featureSet.environment ? "PASS" : "BLOCK");
+        envKeys = new ArrayList<>();
+        envKeys.addAll(this.env.keySet());
 
         if (!featureSet.perl) {
             fingerprintBlackList.add(PERL.INSTANCE.code());

src/main/java/com/falsepattern/jfunge/interpreter/instructions/Funge98.java

@@ -5,6 +5,7 @@
 import com.falsepattern.jfunge.interpreter.instructions.fingerprints.BASE;
 import com.falsepattern.jfunge.interpreter.instructions.fingerprints.CPLI;
 import com.falsepattern.jfunge.interpreter.instructions.fingerprints.DATE;
+import com.falsepattern.jfunge.interpreter.instructions.fingerprints.EVAR;
 import com.falsepattern.jfunge.interpreter.instructions.fingerprints.FPDP;
 import com.falsepattern.jfunge.interpreter.instructions.fingerprints.FPSP;
 import com.falsepattern.jfunge.interpreter.instructions.fingerprints.HRTI;
@@ -49,6 +50,7 @@ public class Funge98 implements InstructionSet {
         addFingerprint(BASE.INSTANCE);
         addFingerprint(CPLI.INSTANCE);
         addFingerprint(DATE.INSTANCE);
+        addFingerprint(EVAR.INSTANCE);
         addFingerprint(FPSP.INSTANCE);
         addFingerprint(FPDP.INSTANCE);
         addFingerprint(HRTI.INSTANCE);

src/main/java/com/falsepattern/jfunge/interpreter/instructions/fingerprints/EVAR.java

@@ -0,0 +1,63 @@
+package com.falsepattern.jfunge.interpreter.instructions.fingerprints;
+
+import com.falsepattern.jfunge.interpreter.ExecutionContext;
+import com.falsepattern.jfunge.interpreter.instructions.Fingerprint;
+import lombok.NoArgsConstructor;
+import lombok.val;
+
+@NoArgsConstructor(access = lombok.AccessLevel.PRIVATE)
+public class EVAR implements Fingerprint {
+    public static final EVAR INSTANCE = new EVAR();
+    @Override
+    public int code() {
+        return 0x45564152;
+    }
+
+    @Instr('G')
+    public static void getEnvironmentVariable(ExecutionContext ctx) {
+        val stack = ctx.stack();
+        val key = stack.popString();
+        val value = ctx.env().get(key);
+        if (value == null) {
+            ctx.interpret('r');
+            return;
+        } else {
+            stack.pushString(value);
+        }
+    }
+
+    @Instr('N')
+    public static void getEnvironmentVariableCount(ExecutionContext ctx) {
+        ctx.stack().push(ctx.envKeys().size());
+    }
+
+    @Instr('P')
+    public static void setEnvironmentVariable(ExecutionContext ctx) {
+        val stack = ctx.stack();
+        val keyValuePar = stack.popString();
+        val equalsIndex = keyValuePar.indexOf('=');
+        if (equalsIndex == -1) {
+            ctx.interpret('r');
+            return;
+        }
+        val key = keyValuePar.substring(0, equalsIndex);
+        val value = keyValuePar.substring(equalsIndex + 1);
+        if (!ctx.env().containsKey(key)) {
+            ctx.envKeys().add(key);
+        }
+        ctx.env().put(key, value);
+    }
+
+    @Instr('V')
+    public static void getEnvironmentVariableAtIndex(ExecutionContext ctx) {
+        val stack = ctx.stack();
+        val index = stack.pop();
+        val keys = ctx.envKeys();
+        if (index < 0 || index >= keys.size()) {
+            ctx.interpret('r');
+            return;
+        }
+        val key = keys.get(index);
+        stack.pushString(key + "=" + ctx.env().get(key));
+    }
+}