[Haskell-cafe] About using "type" to do type alias.

[Ivan Lazar Miljenovic]

On 25 June 2012 12:50, Magicloud Magiclouds
<magicloud.magiclouds at gmail.com> wrote:
> Hi,
>  There was another mail, but the subject might be confusing. So I
> write this one. The code is here: http://hpaste.org/70414
>  If I understand correct, generally, I could use 'type' to do alias
> to save the ugly-long code. Like section 1. This works when I 't [(0,
> Just "x")]'.
>
>  But, if I wrote section 2. Then 'start (M.fromList $ zip ord_args)
> worker' could not be compiled due to the second argument is type of
> 'M.Map Arg Arg', not 'JobArgs Arg Arg'.

This shouldn't make a difference.  As an example, this works:

> import qualified Data.Map as M
>
> type Foo a b = M.Map a b
>
> fooInsert :: (Ord a) => a -> b -> Foo a b -> Foo a b
> fooInsert = M.insert

Aliases are just for documentation; they shouldn't affect code working.


>
>  What did I miss to make this work?
> --
> 竹密岂妨流水过
> 山高哪阻野云飞
>
> And for G+, please use magiclouds#gmail.com.
>
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe



-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
http://IvanMiljenovic.wordpress.com