From IFWiki

Visionary is an authoring system that can create new games in the Scott Adams Classic Adventure (SACA) format. It was created by therealeasterbunny who used it to make R (Pron: Arrr...) for the IF Comp 2010 competition.

Visionary is currently free to use and its Visual Basic 6 source code is available. Note that Visionary only runs on MS Windows.