[Haskell-cafe] Re: What I wish someone had told me...

[Daryoush Mehrtash]

I am having hard time understanding this statement:

Haskell types lack constructors, so the user never expects to be
> able to conjure up a value of an unknown type.
>

I am not sure how say in a Java language a constructor can "conjure up a
value of an unknown type".

daryoush

On Wed, Oct 15, 2008 at 12:55 PM, Bulat Ziganshin <bulat.ziganshin at gmail.com
> wrote:

> Hello Daryoush,
>
> Wednesday, October 15, 2008, 10:56:39 PM, you wrote:
>
> > If you notice  java generics has all sort of gotchas (e.g.
> > http://www.ibm.com/developerworks/java/library/j-jtp01255.html).  I
>
> large prob;em of OOP languages with generics is interaction between
> those two types of polymorhism. covariant/contravariant typing is one
> example. since Haskell lacks OOP classes, it doesn't have such
> pronblem at all. overall, speaking, pure languages (pure OOP, pure FP,
> pure LP) is much simpler than ones trying to combine OOP, FP and
> everything else together. There Is Only One Way To Do It In Haskell ;)
>
>
> --
> Best regards,
>  Bulat                            mailto:Bulat.Ziganshin at gmail.com
>
>
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