Re: [Haskell-cafe] Bug in Hugs, Haskell behavior question

Derek: yes, I caught this in the language description not long after hitting "send": I had forgotten about that. But then I anticipated the behavior Ryan shows below, where using a variable that's part of a "strange" pattern will cause an error (I didn't want to check it while driving home--cell phone user/drivers are bad enough!--so thanks, Ryan, for verifying :) ). In any case, opinions about the behavior aside, there is a Hugs internal error here, so I hope that much is useful. The strange cases make for interesting academic discussions, at least. -- Fritz On Fri 4 Apr 08, at 6:49 pm, Derek Elkins wrote:

Top-level bindings are irrefutable, so 2 = 3 is fine, if vacuous.

On Fri 4 Apr 08, at 6:53 pm, Ryan Ingram wrote:

On 4/4/08, Fritz Ruehr wrote:

...

In fact, even this goes through without a hitch!

2 = 3

This is hilarious.

Maybe bindings that don't actually bind anything should be an error? Or at least a warning?

In ghci:

Prelude> let 2 = 3 -- no problem Prelude> let (2,x) = (3,4) -- no problem Prelude> x *** Exception: <interactive>:1:4-16: Irrefutable pattern match failed for pattern (2,x)

-- ryan