You can be cute and use the applicative instance on functions: (&&) <$> pred1 <*> pred2. I would recommend against such cuteness however and just write out the arguments. On Mon, 16 Nov 2015 at 11:54 emacstheviking wrote:

I guess it depends on the final use cases... you could use currying to partially evaluate some stuff ready, locked and loaded as it were but the example you have given shows to distinct functions pres1 and pred2.

I guess the short answer is "yes" but it depends on how you do it!

:) Sean

On 16 November 2015 at 11:44, Mark Carter wrote:

...

Suppose I want to use an argument twice, as for example in the expression: (\x -> (pred1 x) and (pred2 x))

Is there a shorter way of doing this? _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

And here's the arrow implementation (pred1 &&& pred2) >>> uncurry (&&) You need Data.Tuple (for uncurry) and Data.Arrow. On Mon, Nov 16, 2015 at 5:40 PM, Frerich Raabe wrote:

On 2015-11-16 12:44, Mark Carter wrote:

...

Suppose I want to use an argument twice, as for example in the expression: (\x -> (pred1 x) and (pred2 x))

Is there a shorter way of doing this?

I suppose you meant to write '&&' instead of 'and'?

You can write it in an applicative style as

(&&) <$> pred1 <*> pred2

If you like, you can shorten that a bit using 'liftA2' as

liftA2 (&&) pred1 pred2

but I personally tend to like the former version better.

-- Frerich Raabe - raabe@froglogic.com www.froglogic.com - Multi-Platform GUI Testing

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners