[Haskell-cafe] Language extensions [was: Memoization]

[Andrew Coppin]

apfelmus wrote:
> Andrew Coppin wrote:
>   
>>>> OOC, can anybody tell me what ∀ actually means anyway?
>>>>         
>
> http://en.wikipedia.org/wiki/Universal_quantification
> http://en.wikipedia.org/wiki/System_F
>   

So... ∀x . P means that P holds for *all* x, and ∃ x . P means that x 
holds for *some* x? (More precisely, at least 1 possible choice of x.)

>> I do recall that GHC has some weird extension called "existential
>> quantification"
>>     
>
> http://haskell.org/haskellwiki/Existential_types
> http://en.wikibooks.org/wiki/Haskell/Existentially_quantified_types
>   

Erm... oh...kay... That kind of makes *slightly* more sense now...

Seriously. Haskell seems to attract weird and wonderful type system 
extensions like a 4 Tesla magnet attracts iron nails... And most of 
these extensions seem to serve no useful purpose, as far as I can 
determine. And yet, all nontrivial Haskell programs *require* the use of 
at least 3 language extensions. It's as if everyone thinks that Haskell 
98 sucks so much that it can't be used for any useful programs. This 
makes me very sad. I think Haskell 98 is a wonderful language, and it's 
the language I use for almost all my stuff. I don't understand why 
people keep trying to take this small, simple, clean, elegant language 
and bolt huge, highly complex and mostly incomprehensible type system 
extensions onto it...