Hi Alvaro,

I think you need something wha Scala has - the ability to create a partial function from a case expression. In Scala you could write

def update[A](f: PartialFunction[A,A])(v: A): A =

f.orElse({ case x => x } : PartialFunction[A,A]).apply(v);

and then use it like

update[Int]({ case Foo => Bar })

But AFAIK there is nothing like this in Haskell. Maybe separating 'of' from 'case' would be the way to extend Haskell with such a feature <http://www.haskell.org/pipermail/haskell-cafe/2012-November/104884.html>

Best regards,

Petr

2012/12/21 Radical <radical@google.com>

Sometimes I'll need something like:

if value == Foo then Bar else value

Or some syntactic variation thereof:

case value of { Foo -> Bar; _ -> value }

Is there a better/shorter way to do it? I'm surprised that it's more complicated to substitute a value on its own than e.g. in a list, using filter. Or perhaps I'm missing the right abstraction?

Thanks,

Alvaro

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