[saosebastiao]

It wasn't really used for anything before, because of the bizarre custom license.

However, it looks like it has a lot of interesting features that people might want to use. For example, it can be trivially embedded in pretty much any other language by implementing a handful of core functions. It has an embedded prolog DSL. It has pattern matching, static type checking, lazy evaluation.

[Igglyboo]

I just read over the license, didn't see too weird except the part about the spec. If I read it correctly you can't modify shen if your modifications don't conform to the specification.

[hga]

The problem is the license tries to say the same thing at least 3 times, and that results in tremendous ambiguity.

If you wanted to use it commercially and safely, you'd have to spend quite a bit on an IP lawyer with no guarantee he'd give you an OK. In a universe with so many good languages, many with much bigger communities (in part because of the license), with well understood and often tested in court licences, it's a non-starter.

The intent is fine, everybody's code will run on your port, modulo bugs, and is plainly stated in the last line of the licence: “Thou shalt not break the spec” It's the execution by someone who's a computer scientist, not a lawyer, nor very familiar with IP law.