Fix parsing of literate CoffeeScript.

Author: benjie

src/helpers.coffee

@@ -136,3 +136,14 @@ exports.nameWhitespaceCharacter = (string) ->
     when '\r' then 'carriage return'
     when '\t' then 'tab'
     else string
+
+exports.invertLiterate = (code) ->
+  maybe_code = true
+  lines = for line in code.split('\n')
+    if maybe_code and /^([ ]{4}|[ ]{0,3}\t)/.test line
+      line
+    else if maybe_code = /^\s*$/.test line
+      line
+    else
+      '# ' + line
+  lines.join '\n'

src/parser.coffee

@@ -1,6 +1,6 @@
 
 # Import the helpers we need.
-{count, starts, compact, last, repeat, throwSyntaxError} = require './helpers'
+{count, starts, compact, last, repeat, throwSyntaxError, invertLiterate} = require './helpers'
 
 $ = require './symbols'
 
@@ -305,6 +305,7 @@ module.exports = class Parser
   clean: (code) ->
     code = code.slice(1) if code.charCodeAt(0) is BOM
     code = code.replace(/\r/g, '') # strip carriage return chars
+    code = invertLiterate code if @opts?.literate
     code
 
   # Returns the line and column number from an offset into the current chunk.