[lsb]

Actually, case is built into Haskell: it's the evaluation primitive in Haskell Core; see Don Stewart's blog post http://cgi.cse.unsw.edu.au/~dons/blog/2008/05/16 .

[eru]

Yes, there it is. Sorry, I did not research my claim.

Actually pattern matching can also be described as something like a case-switch.