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 6:53 pm, Ryan Ingram wrote:

On 4/4/08, Fritz Ruehr <fruehr@willamette.edu> 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