Re: [Haskell-cafe] An interesting curiosity

2008/9/18 Evan Laforge :

...

All of this works of course because in Haskell, "=" is not an assignment, it's a definition, and the RHS is not a variable, it's a pattern. And "4" is a perfectly legitimate pattern. Now, if only I could find a use for all this that borders on "useful"...! ;-)

I like this one:

let {1 + 1 = 3; 3 + 1 = 3} in 1 + 1 + 1

Right answer, for the wrong reasons. Useful? Well... does confusing people count as useful?

Well, Andrew says it himself : it's practical because you can pattern match against specific value : f [] = ... f (4:xs) = ... f (x:xs) = ... Thu