[Haskell-beginners] Trivial function of type (a -> b) -> Maybe a -> Maybe b

[Yusaku Hashimoto]

> Sure that is it. I should pay more attention to standard type classes.

Typeclassopedia will help you to understand these type classes:
http://www.haskell.org/sitewiki/images/8/85/TMR-Issue13.pdf

-- nwn

On Thu, Jan 14, 2010 at 12:01 AM, Eugen Zagorodniy
<e.zagorodniy at gmail.com> wrote:
> Wed, 13 Jan 2010 08:47:42 -0600 Antoine Latter:
>> On Wed, Jan 13, 2010 at 8:44 AM, Eugen Zagorodniy
>> <e.zagorodniy at gmail.com> wrote:
>> > Greetings!
>> >
>> > I looked at documentation of Maybe type and suprisingly found no
>> > function like
>> >
>> > maybize             :: (a -> b) -> Maybe a -> Maybe b
>> > maybize f Nothing   =  Nothing
>> > maybize f (Just x)  =  Just (f x)
>> >
>>
>> Have you looked at:
>>
>> fmap :: Functor f => (a -> b) -> f a -> f b
>>
>> It will do what you want, and has the bonus of doing the same
>> operation for a lot more structures.
>
> Sure that is it. I should pay more attention to standard type classes.
>
> Thanks!
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