itch.io

FlashDevelop is a free and open source code editor for every developer

FlashDevelop offers first class support for ActionScript (2 & 3) and Haxedevelopment. Great completion & code generation, projects compilation & debugging, plenty of project templates, SWF/SWC exploration etc. FlashDevelop
is also a great web development IDE with source-control support (svn, git, mercurial), tasks, snippets, XML/HTML completion and zen-coding for HTML.