Add basic line number and character support to exceptions

lib/hjson/ast/nodes/any.rb

@@ -12,7 +12,7 @@ class Any < Node
 
       parser do
         if punctuator?
-          fail SyntaxError, 'Any value does not expected %p' % char
+          fail SyntaxError.new(self, ('Any value does not expect %p' % char))
         end
       end
       parser do

lib/hjson/ast/nodes/array.rb

@@ -18,7 +18,7 @@ class Array < Node
           end
         end
       end
-      parser { fail EndOfInputError }
+      parser { fail EndOfInputError.new(self) }
     end
   end
 end

lib/hjson/ast/nodes/keyname.rb

@@ -15,17 +15,17 @@ class Keyname < Node
       parser do
         until eos?
           if colon?
-            fail SyntaxError if payload.empty?
+            fail SyntaxError.new(self) if payload.empty?
             if positive?(space) && space != payload.length
               buffer.pos = start + space
-              fail SyntaxError
+              fail SyntaxError.new(self)
             end
             halt(payload)
           elsif char <= ' '
-            fail SyntaxError if eos?
+            fail SyntaxError.new(self) if eos?
             self.space = payload.length if negative?(space)
           elsif punctuator?
-            fail SyntaxError
+            fail SyntaxError.new(self)
           else
             payload << char
           end

lib/hjson/ast/nodes/multiline.rb

@@ -24,7 +24,10 @@ class Multiline < Node
 
       parser do
         loop do
-          fail SyntaxError unless char
+          unless char
+            fail SyntaxError.new(self)
+          end
+
           if single_quote?
             self.triple += 1
             read

lib/hjson/ast/nodes/object.rb

@@ -32,7 +32,7 @@ class Object < Node
         if without_braces?
           halt(payload)
         else
-          fail EndOfInputError
+          fail EndOfInputError.new(self)
         end
       end
     end

lib/hjson/ast/nodes/string.rb

@@ -20,7 +20,7 @@ class String < Node
 
       declare :payload, ''
 
-      parser { fail SyntaxError unless double_quote? }
+      parser { fail SyntaxError.new(self) unless double_quote? }
       parser do
         while read
           halt(read && payload) if double_quote?
@@ -48,7 +48,7 @@ def read_escapee
       def read_unicode
         uffff = 4.times.reduce(0) do |i, _|
           read
-          fail SyntaxError unless hex?
+          fail SyntaxError.new(self) unless hex?
           hex = char.to_i(16)
           break if hex.infinite?
           i * 16 + hex

lib/hjson/ast/parser.rb

@@ -45,6 +45,10 @@ def initialize(buffer, **options)
         assign_declared_vars!
       end
 
+      def current_line_number
+        string[0..pos].count("\n") + 1
+      end
+
       private
 
       def assign_declared_vars!
@@ -62,8 +66,10 @@ def assign_declared_vars!
 
       def validate(expected)
         current = current_char
-        fail SyntaxError,
-          "Expected %p instead of %p" % [expected, current] if expected && expected != current
+
+        if expected && expected != current
+          fail SyntaxError.new(self, ("Expected %p instead of %p" % [expected, current]))
+        end
       end
 
       def halt(data = nil)

lib/hjson/errors.rb

@@ -1,5 +1,13 @@
 module Hjson
-  Error           = Class.new(StandardError)
+  class Error < StandardError
+    def initialize(parser, message = "")
+      message.prepend("L#{parser.current_line_number}:#{parser.charpos} ")
+      message.strip!
+
+      super(message)
+    end
+  end
+
   SyntaxError     = Class.new(Error)
   EndOfInputError = Class.new(Error)
 end