[Haskell-cafe] Pattern matching with where free variables can be used more than once

[Stefan Holdermans]

Christopher,

> Wouldn't it be great if pattern variables could be used more than once
> in a pattern? Like so:
>
>    foo [x,x,_,x] =  "The values are the same!"
>    foo _      = "They're not the same!"

These are called nonlinear patterns. I think Miranda (a precursor of  
Haskell, sort of) used to have them.

Cheers,

   Stefan