Common syntax for casing/matching (Re[2]: Call to arms: lambda-case is stuck and needs your help)

[Twan van Laarhoven]

On 2012-07-12 23:48, Bulat Ziganshin wrote:
> another interesting feature may be ruby-style matching defined by
> execution of special function `match` instead of pattern matching:
>
> switch var of
>    1+1     -> print "var==2"
>    [5..10] -> print "var in [5..10]"
>    (>20)   -> print "var>20"
>
> where (var `match` (1+1)), (var `match` [5..10]), (var `match` (>20)) is tested

With view patterns you can write

     case var of
         ((== 1+1)         -> True) -> print "var==2"
         ((`elem` [5..10]) -> True) -> print "var in [5..10]"
         ((> 20)           -> True) -> print "var>20"

Or you can just use guards, of course.


Twan