ax4

ax4 is an ActionScript 3 to Haxe converter that tries to be very smart and precise about rewriting code. To achieve that, it actually resembles the typical compiler a lot, so here's how it works:

• parse AS3 modules into the ParseTree structure, containing all the syntactic information
• load classes and signatures from the SWC libraries so we have the external type information
• process ParseTree and build the TypedTree, resolving all imports and type references and assigning type to every piece of code
• run a sequence of "filters" which analyze and re-write the TypedTree structures to adapt the code for Haxe
• generate Haxe modules from the processed TypedTree

Disclaimer

ax4 is a fork of ax3, created by Dan Korostelev (nadako) at InnoGames, by way of another fork. I developed ax4 to make a fan-made native port of Dungeon Rampage (see Dungeon Rampage Haxe).

I may or may not continue to maintain ax4, and port other games in the future.

Quick start

1) Install

With a Java runtime and haxelib:

haxelib install ax4

To build it from source instead, see Quickstart.

2) Create a minimal config.json

{
  "src": "path/to/as3/src",
  "hxout": "path/to/haxe/out",
  "swc": [
    "path/to/playerglobal.swc"
  ]
}

3) Run conversion

haxelib run ax4 config.json

Documentation

• Home
• Quickstart
• Config reference
• Config examples
• Differences from ax3
• Filters overview
• Diagnostics catalogue
• Troubleshooting
• Contributing
• GitHub wiki setup and sync

Compat runtime

• compat/ contains AS3 compatibility/runtime helpers used by generated Haxe code (ASAny, ASDictionary, XML helpers, etc.).
• Converted code depends on this layer: with the haxelib install, add -lib ax4 to your Haxe build; otherwise copy compat/ with the copy option (see Quickstart).
• compat-test/ contains tests for the compatibility layer itself and is not meant to be shipped with production output.
• If you modify compat/, update compat-test/ and run:

npx haxe test-compat.hxml

Conversion Pipeline

The pipeline is implemented in src/ax4/Main.hx:

1. Parse AS3 into ParseTree
2. Load SWC externs/signatures
3. Type into TypedTree
4. Run rewrite filters
5. Generate Haxe modules

Known limitations

• The parser doesn't currently support ASI (automatic semicolon insertion). The only case where a semicolon can be omitted is the last expression of a block.
• Only a small, most commonly used subset of E4X is supported. It's recommended to rewrite the unsupported things in AS3 sources to adapt it for conversion.
• XML literals (<a>...</a>) are not supported: skipXmlLiterals comments them out as null.
• Some forms stop the conversion, such as a case after default or a split with a limit.