herrhotzenplotz / lc

Untyped Lambda Calculus Interpreter in Haskell

Untyped lambda calculus interpreter

Just something I did in my spare time.

Quick start

$ git clone [e-mail]:herrhotzenplotz/lc
$ cd lc/
$ stack build
$ stack run

Examples to try

• (\x.x \y.y)
• ((\x.\y.(x y) \f.f) \r.r)
• let true = \x.\y.x
• let false = \x.\y.y
• let not = \b.((b false) true)
• (not false)
• release true (removes globally bound true)

Loading files

$ lc bool.lc fixpoint.lc

Notes

Because the interpreter internally uses closures, you might sometimes be getting seemingly incorrect results. These results should start with a ' sign, showing that this result still has values bound in the closure, that have not yet been applied. This is the lazy evaluation mechanism. To force a result, simply apply an identity function or something else to force the lazy thunk to evaluate.

Contributions

If you want to submit pull requests or file issues, please feel free to do that. I'll address them as soon as I can.

License

The lc is released under a three clause BSD license. Please see the LICENSE file.