On 6 October 2010 11:39, Simon Marlow
Certainly some existing code would fail to parse, e.g. (case e of [] -> \x -> x+1; (x:xs) -> \x -> x+2)
That's definitely a problem. The multi-pattern lambda is nice as I think it follows naturally from function definitions (indeed, I think many a Haskeller including myself have written (\x -> k; \y -> l) once expecting it to work), but problems like this are kind of a deal breaker.
A slightly different suggestion from Simon PJ and myself (we agreed on something syntax-related :-) is the following:
\case 1 -> f 2 -> g ... \case { 1 -> f; 2 -> g }
+1 I like this because it has exactly the same properties of Max's case-of, but is shorter and still reads with sense. I created a poll about for/against the case-of idea, but it seems, just from the messages here, unanimous that people *do* want something like this, mostly to solve the unnecessary/dummy formal parameters problem.