Re: Case expressions in STG

Ah, yes, that's what I meant. I see your point about your example, now. Will

On Jun 19, 2014, at 3:27 AM, Tom Ellis wrote:

...

On Wed, Jun 18, 2014 at 07:40:26PM -0400, William Knop wrote: f = \x -> x g = \x -> (x,1) h = \x -> fst (g x) i = \x -> case f of f -> True _ -> False

i f => True i h => ?

If g isn't inlined into h and fst optimized out, wouldn't the head normal form of f and h be different, and the comparison fail even though it shouldn't? Or should it? I've taken function equality to be "f and g are equal iff f x == g x, for all x."

You mean 'i = \x -> case x of' ...

Anyway, I'm not suggesting using case to *compare* functions, simply force their thunk before proceeding with a single default alternative.

Tom _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs