Source Code

ECMAScript is a scripting engine that supports most of the ECMAScript language.

Some new language features were added, such as coroutines, and the ability to suspend code in mid-run.

More details at (English) or read about yossy's original engine in Japanese at .


  • This is a port of yossy's original ECMAScript scripting engine in AS2.
  • It was ported to AS3.
  • Some bugs were fixed in the language parsing.
  • Added some small features, like runCoroutine() or parseForceCoroutine().
  • Changed the Parser.parse() function to accept a virtual machine as an optional argument. If used, this will optimize the code for that virtual machine, giving a 40% speed increase.
  • More detailed (English, sorry) documentation is in the Source Code folder.