Looks like an interesting project.<p>The license or terms-of-use seem weird: <i>"Picat can be used for any fair purpose, including commercial applications. The C source code is available to registered developers and users free of charge. The project is open to anybody and you are welcome to join, as a developer, a sponsor, a user, or a reviewer. Please contact picat@picat-lang.org"</i><p>Why make things complicated with these conditions? If you are going to allow source access, why not use a standard open source license. If you aren't, if you want to control of the language for some purpose, make it clear this is a commercial product.<p>The GPL (and other standard open source licenses) are a real commercial licenses at this point. Roll-your-own software licenses seem a lot like roll-your-own device device drivers - might have made sense in yesterday's world but not today.