[Haskell-cafe] Arrows extentions and ArrowApplicable

28 Aug 2009

      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

but

proc x -> do
	a <- someArrow -< x
	app -< (a, x)

and

proc x -> do
	a <- someArrow -< x
	app -< (otherArrow a, x)

instead of

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

Such approach adds some syntax sugar but without adding any additional
keyword and IMHO it can simplify writing ArrowApply (especially Kleisli
IO).

Regards

[Haskell-cafe] Arrows extentions and ArrowApplicable

Maciej Piechotka