Re: [Caml-list] how to start

Re: [Caml-list] how to start

[MONIN Jean-Francois FTRD/DTL/LAN]

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> # type idref={ mutable id : 'a. 'a -> 'a};;
> what does "." mean?

This just a separator. 
You can read 'a. 'a -> 'a  as  (forall 'a) 'a -> 'a

  Jean-Francois Monin

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[Caml-list] how to start

[climb]

Dear caml-list
 
 i am a new commer of Caml language. and start with online mannul
 i am confused at this sentence in Chapter 1
# type idref={ mutable id : 'a. 'a -> 'a};;
what does "." mean?

why i can not write 
# type intidref= { mutable id : int. int->int};;

 

thanks
                         climb
                         onlyclimb@163.com
                         2002-10-16

 



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Re: [Caml-list] how to start

[Chris Hecker]

>  i am a new commer of Caml language. and start with online mannul
>  i am confused at this sentence in Chapter 1
># type idref={ mutable id : 'a. 'a -> 'a};;
>what does "." mean?
>why i can not write
># type intidref= { mutable id : int. int->int};;

This is a new feature in the language, and you really don't need to learn 
it quite yet if you're just starting out.  Basically, before the 'a. syntax 
was introduced, there was no way to store some kinds of functions 
(polymorphic ones) in datastructures.  You don't need int. int->int because 
that's not a polymorphic function, so it's just int -> int.

I'd just ignore it for now.  :)  You should also check out the O'Reilly 
book referenced on http://caml.inria.fr

Chris


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