14 Oct
2009
14 Oct
'09
6:15 a.m.
On Wed, Oct 14, 2009 at 11:53 AM, Dan Doel
In fact, with GHC extensions, you don't need newtypes: {-# LANGUAGE LiberalTypeSynonyms #-} Ah, I completely forgot about that language extension. Thanks!
Yeah. Asking for the type of 'f4 . f4' doesn't seem to expand the synonyms, while checking f5 does for some reason. I'm perplexed that having f5 defined in the file doesn't trigger the explosion unless you declare a type (even in terms of X and T) or ask for its type at the prompt. If you declare a type for f5 then ghci must check if that type is correct, which triggers the explosion. If you don't declare a type then it won't infer the type until necessary. Basically, ghci is lazy :-)