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

Alexey Romanov alexey.v.romanov at gmail.com
Tue Oct 14 14:28:06 EDT 2008


On Tue, Oct 14, 2008 at 9:14 PM, Jonathan Cast
<jonathanccast at fastmail.fm> wrote:
> On Tue, 2008-10-14 at 18:15 +0100, John Lato wrote:
>> Are you advocating introducing existential types to beginning
>> Haskellers?  I think something with the scary name
>
> Invalid argument.
>
>> "existential
>> quantification" would greatly increase the head'splodin' on the
>> learnin' slope.
>
> Invalid argument.  Head explosion is the *goal* of teaching Haskell.

Is it? I would certainly prefer my students to say "This is obvious. Why would
things work in any other way?" They don't, but I can dream.

>> Certainly there's a place for them, but I wouldn't
>> want to see new Haskell programmers habitually approach problems with
>> a "first create a type class, then make an existential wrapper"
>> mentality.
>
> Of course not.  That's just translating OO into Haskell.  Personally, I
> would avoid comparing Haskell to other language at all (SOE I believe
> takes this approach).
>
> jcc

I find such comparisons pretty useful.

Yours, Alexey Romanov


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