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

Ralf Hinze ralf at informatik.uni-bonn.de
Fri Dec 23 03:52:00 EST 2005

> 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


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

Cheers, Ralf

More information about the Haskell-Cafe mailing list