[Haskell-cafe] Type-Level Programming
Andrew Coppin
andrewcoppin at btinternet.com
Sat Jun 26 14:21:50 EDT 2010
Alexander Solla wrote:
>
> On Jun 26, 2010, at 4:33 AM, Andrew Coppin wrote:
>
>> It's a bit like trying to learn Prolog from somebody who thinks that
>> the difference between first-order and second-order logic is somehow
>> "common knowledge".
>
>
> A first order logic quantifies over values, and a second order logic
> quantifies over values and sets of values (i.e., types, predicates,
> etc). The latter lets you express things like "For every property P,
> P x". Notice that this expression "is equivalent" to Haskell's bottom
> type "a". Indeed, Haskell is a weak second-order language. Haskell's
> language of values, functions, and function application is a
> first-order language.
I have literally no idea what you just said.
It's like, I have C. J. Date on the shelf, and the whole chapter on the
Relational Calculus just made absolutely no sense to me because I don't
understand the vocabulary.
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