...! language constructs were designed to map cleanly to 6502 opcodes.
In 2015, Clinton Parker released the Action! 3.6 source code to the public under the terms of GPL. This project is intended to preserve the Action! source code, provide fixes for known bugs, and add new features in version 3.7.
Join us at AtariAge https://forums.atariage.com/topic/217770-action-source-code for questions and discussions.
Check out https://atariwiki.org/wiki/Wiki.jsp?page=Action for related information.