[Haskell-cafe] How is laziness defined?

[ajb at spamcop.net]

G'day all.

Quoting Matthew Brecknell <haskell at brecknell.org>:

> Although it covers irrefutable (lazy) pattern matching in the second
> section, it does appear to miss the point that let bindings are always
> irrefutable.
>
> Thus, there is no difference between these two:
>
> let (x,y) = foo in ...
> let ~(x,y) = foo in ...

let (x,()) = (1,undefined) in x
let (x,~()) = (1,undefined) in x

Cheers,
Andrew Bromage