Implement gensym

[hrs]

Implement gensym

[hrs]

It looks like Common Lisp handles this by using a module system for namespacing and then putting each gensym in its own module. Maybe we should implement modules?

[hrs]

I don't see myself implementing modules in Blueprint in the foreseeable future (or, realistically, probably ever), but I'd still like to include gensym before I call Blueprint "finished."

One way might be to always include a character in the generated symbols that the parser wouldn't ordinarily accept. Lisps often use # for gensyms, but those indicate comments in Blueprint. We don't accept @ in symbols, though, and they're not used in anything else, so that could be a good candidate.

Maybe gensyms should have the form @<gensym-12345>, where the number is unique. That number might come off a global counter (start at 1 and increment each time), or maybe we'd rather use a timestamp (there's no parallelism, though, so there should never be a race for that counter).