added nice syntax errors

lib/coffee_script/command_line.rb

@@ -31,7 +31,7 @@ Usage:
     def compile_javascript
       @sources.each do |source|
         next tokens(source) if @options[:tokens]
-        contents = CoffeeScript.compile(File.open(source))
+        contents = compile(source)
         next puts(contents) if @options[:print]
         next lint(contents) if @options[:lint]
         File.open(path_for(source), 'w+') {|f| f.write(contents) }
@@ -60,6 +60,15 @@ Usage:
       puts Lexer.new.tokenize(File.read(source)).inspect
     end
 
+    def compile(source)
+      begin
+        CoffeeScript.compile(File.open(source))
+      rescue CoffeeScript::ParseError => e
+        STDERR.puts e.message(source)
+        exit(1)
+      end
+    end
+
     # Write out JavaScript alongside CoffeeScript unless an output directory
     # is specified.
     def path_for(source)

lib/coffee_script/grammar.y

@@ -294,13 +294,16 @@ rule
 end
 
 ---- inner
-  def parse(code, show_tokens=false)
+  def parse(code)
     # @yydebug = true
     @tokens = Lexer.new.tokenize(code)
-    puts @tokens.inspect if show_tokens
     do_parse
   end
 
   def next_token
     @tokens.shift
+  end
+
+  def on_error(error_token_id, error_value, value_stack)
+    raise CoffeeScript::ParseError.new(token_to_str(error_token_id), error_value, value_stack)
   end

lib/coffee_script/parse_error.rb

@@ -0,0 +1,19 @@
+module CoffeeScript
+
+  class ParseError < Racc::ParseError
+
+    def initialize(token_id, value, stack)
+      @token_id, @value, @stack = token_id, value, stack
+    end
+
+    def message(source_file=nil)
+      line      = @value.respond_to?(:line) ? @value.line : "END"
+      line_part = source_file ? "#{source_file}:#{line}:" : "line #{line}:"
+      id_part   = @token_id != @value.inspect ? ", unexpected #{@token_id.downcase}" : ""
+      "#{line_part} syntax error for '#{@value.to_s}'#{id_part}"
+    end
+    alias_method :inspect, :message
+
+  end
+
+end