[Haskell-cafe] Re: help with Haskell programming

Mujtaba Boori mujtaba.boori at gmail.com
Sun Apr 18 13:40:31 EDT 2010


Thanks a lot guys you were really helpful

func f1 f2 x = (f1 x) || (f2 x) is working for me



On Sun, Apr 18, 2010 at 6:27 PM, Thomas Davie <tom.davie at gmail.com> wrote:

> To do this, you need not just fmap (composition), but also ap, or the
> combined form, liftA2:
>
> func = liftA2 (||)
>
> Bob
>
> On 18 Apr 2010, at 18:21, Keith Sheppard wrote:
>
> > Using composition can be tricky with more than one arg. I just want to
> > be sure you're not really looking for something like:
> >
> >> func :: (a -> Bool) -> (b -> Bool) -> (a -> b -> Bool)
> >
> > keeping with your given type I think you're looking for something like:
> >
> >> func f1 f2 x = (f1 x) || (f2 x)
> >
> > I'm sure there is a nice way to do this with function composition but
> > I still find composition less intuitive than explicit args in cases
> > like this.
> >
> > On Sun, Apr 18, 2010 at 1:00 PM, Mujtaba Boori <mujtaba.boori at gmail.com>
> wrote:
> >> Thanks for helping me but I have another problem (sorry for asking) . I
> >> tried to figure it out .
> >> how about if I want to compare two kind with (&&) (||)  for
> >> func :: (a -> Bool) -> (a -> Bool) -> (a -> Bool)
> >>
> >> I tried some thing like
> >> func = ((||) .)
> >> This is the annoying part about Haskell . I can not understand
> composition .
> >>
> >> On Sun, Apr 18, 2010 at 4:35 PM, Mujtaba Boori <mujtaba.boori at gmail.com
> >
> >> wrote:
> >>>
> >>> Hello I am kinda newbie in Haskell you can help help me with some
> >>> programming
> >>> I am trying to make function like for example
> >>> func :: (a -> Bool) -> (a -> Bool)
> >>> this function make calculation  and return bool . I want to be able to
> >>> make bool True when It is False and False when it is True while
> returning
> >>> the a.
> >>> Thank you
> >>> --
> >>> Mujtaba Ali Alboori
> >>
> >>
> >>
> >> --
> >> Mujtaba Ali Alboori
> >>
> >> _______________________________________________
> >> Haskell-Cafe mailing list
> >> Haskell-Cafe at haskell.org
> >> http://www.haskell.org/mailman/listinfo/haskell-cafe
> >>
> >>
> >
> >
> >
> > --
> > keithsheppard.name
> > _______________________________________________
> > Haskell-Cafe mailing list
> > Haskell-Cafe at haskell.org
> > http://www.haskell.org/mailman/listinfo/haskell-cafe
>
>


-- 
Mujtaba Ali Alboori
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