Re: [Haskell-cafe] Arrows extentions and ArrowApplicable

On Fri, Aug 28, 2009 at 02:33:08PM +0200, Maciej Piechotka wrote:

Arrows syntax supports Arrow, ArrowChoice(if, case etc.) and ArrowLoop(rec) - but not ArrowApplicable. Therefore it is not possible to write:

proc x -> do a <- someArrow -< x a -< x

You can write proc x -> do a <- someArrow -< x a -<< x (See the Arrow notation section of the GHC User's Guide.)