[Haskell-cafe] Comments from OCaml Hacker Brian Hurt

Niklas Broberg niklas.broberg at gmail.com
Fri Jan 16 18:31:24 EST 2009


On Sat, Jan 17, 2009 at 12:14 AM, Anton van Straaten
<anton at appsolutions.com> wrote:
>>> I still think existential quantification is a step too far though. :-P
>>
>> Seriously, existential quantification is a REALLY simple concept, that
>> you would learn week two (or maybe three) in any introductory course
>> on logic. In fact, I would argue that far more people probably know
>> what existential quantification is than that know what a monoid is.
>> :-)
>
> Andrew's core objection here seems reasonable to me.  It was this:
>
>> {-# LANGUAGE ExistentialQuantification #-} is an absurd name and
>> should be changed to something that, at a minimum, tells you it's
>> something to do with the type system.
>
> But I suspect I part company from Andrew in thinking that something like
> ExistentiallyQuantifiedTypes would be a perfectly fine alternative.

Well, I definitely agree to that, but that's not what he wrote in the
post I answered. My point was that existential quantification is
nowhere near scary.

But yes - making the Types part explicit is certainly not a bad idea.
+1 for ExistentiallyQuantifiedTypes.

Cheers,

/Niklas


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