[Haskell-beginners] another type problem

[Sumit Sahrawat, Maths & Computing, IIT (BHU)]

The type of the cons operator (:) is

    (:) :: a -> [a] -> [a]

The way you are invoking it expects it to have the type

    (:) :: a -> Maybe [a] -> [a] -- not valid

One solution is to write such a function yourself, while the other would be
to rewrite your code to invoke it correctly.

On 12 May 2015 at 19:46, Brandon Allbery <allbery.b at gmail.com> wrote:

> On Tue, May 12, 2015 at 10:11 AM, Roelof Wobben <r.wobben at home.nl> wrote:
>
>>  I do not understand what you are saying to me.
>>
>> I know that init produces a Maybe [a] . That is why I did put a Just
>> before it.
>>
>
> You are invoking it again though, and using its result as if it produces
> [a] instead of Maybe [a].
>
> --
> brandon s allbery kf8nh                               sine nomine
> associates
> allbery.b at gmail.com
> ballbery at sinenomine.net
> unix, openafs, kerberos, infrastructure, xmonad
> http://sinenomine.net
>
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-- 
Regards

Sumit Sahrawat
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