[Haskell-cafe] arr f

[Ross Paterson]

On Mon, Jan 30, 2006 at 06:27:12PM +0100, Sven Biedermann wrote:
> Since I want to use the arrow notation, I had a close look at the
> following description, taken from
> http://www.haskell.org/ghc/docs/latest/html/users_guide/arrow-notation.html
> [example in 7.7.1. do-notation for commands]
>
> The arrow I want to create is one to track down dependencies. This
> doesn't seem to work with arrow notation, because in the example above
> 
> 	 g -< 2*y
> 
> isn't used in the following statements but is bound to the next arrow:

No, the output of g is discarded by the arr snd.

For another approach to tracking dependencies, see slides 23-26 of

	http://www.soi.city.ac.uk/~ross/talks/fop.4.ps.gz