[Haskell-cafe] Arrows for invertible programming: Notation question

[Ralf Hinze]

> What does this mean and how do I make it compile?
> 
> mapl{|a, b|arr|} :: (mapl{|a, b|arr|}, ArrowChoice arr, BiArrow arr) => arr a b

It's Generic Haskell source code, see

	http://www.generic-haskell.org/

Generic Haskell is an extension of Haskell that supports generic programming.

Cheers, Ralf