Re: [Haskell-cafe] Functions are first class values in C

On Sat, 22 Dec 2007, Cristian Baboi wrote:

On Sat, 22 Dec 2007 17:13:55 +0200, Philippa Cowderoy wrote:

...

Here's a trivial example that does so:

(\x -> x) (\x -> x)

A lambda calculus classic that doesn't typecheck in Haskell:

(\x -> x x) (\x -> x x)

...

Feel free to try evaluating it!

Thank you for your message.

I tryed and this is what I've got: ERROR - cannot find "show" function for: *** Expression : (\x -> x) (\x -> x) *** Of type : a -> a

Yep, that's because while it can evaluate it down to (\x -> x) your interpreter doesn't know how to print the result. You can demonstrate that it works by then passing in something to that result though: ((\x ->x) (\x -> x)) 1 You'll have to evaluate the other one by hand. Don't spend too long with it though! -- flippa@flippac.org "The reason for this is simple yet profound. Equations of the form x = x are completely useless. All interesting equations are of the form x = y." -- John C. Baez