Simple Type Inference in 21 Lines of Clojure

https://gist.github.com/997140

by swannodette • 15 years ago

39 11 15 years ago

gist.github.com

fogus• 15 years ago

Macros and logic engine versus type system... to the death.

davidmathers• 15 years ago

Explain.

swannodette5• 15 years ago

You can get a typed Lisp with just macros, see Typed Racket. What's interesting is whether macros + logic engine will allow a programmer to devise much more powerful guarantees than is possible in any specific type system.

rikthevik• 15 years ago

I think that with ten pages of documentation, the author might really be on to something here.

swannodette5• 15 years ago

Yes, core.logic is definitely in need of more documentation. However it is under heavy development and I'm still unwilling to commit to some design choices just yet.

Even with documentation, I'll never be able to do justice to the art of logic programming - if you're willing to pick up The Reasoned Schemer you'll understand exactly how core.logic works and any good Prolog book will take you the rest of the way.

swannodette5• 15 years ago

Author there. Let me explain - core.logic is a Prolog-like logic engine written in Clojure. It is in fact so similar to Prolog that it's actually quite trivial to port Prolog code as I've done here. The other nice bit is that core.logic is quite fast - it is not the toy implementation of Prolog that you see so often.

UPDATE: edited the examples to show concrete types so it's easier to understand.

sitkack• 15 years ago

See http://vimeo.com/22606387

Kostis Sagonas goes over PropEr and Dialyzer for Erlang.

http://groups.google.com/group/erlang-programming/browse_thr...

http://dialyzer.softlab.ntua.gr/

With these two tools one can have a stronger type system than Haskell. PropEr is amazing work. Not to mention CED https://github.com/mariachris/CED which checks all possible state transitions for race conditions.

swannodette5• 15 years ago

Yes, Dialyzer is quite cool. However it is run as a separate tool on your Erlang source right? What I'm aiming for is something that can be used interactively while at the REPL - Qi/Shen is the inspiration here.

Simple Type Inference in 21 Lines of Clojure

Related Stories