Version française
Home     About     Download     Resources     Contact us    

This site is updated infrequently. For up-to-date information, please visit the new OCaml website at

Browse thread
[Caml-list] list in functional style
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: 2001-08-07 (12:42)
From: Frank Atanassow <franka@c...>
Subject: Re: [Caml-list] list in functional style
Costin Stefan wrote (on 07-08-01 12:41 +0300):
> I have the following problem : want to define lists but using only
> functions :

Sorry, I was not reading very carefully and now recognize that my post was a
complete non-answer.

> So why the type of the result of hd may be the same of the type of the
> result of tl !
> Why the type of the result of a cons isn't a polymorphic function ?

Type variables of the form '_a are not generalized; they can be instantiated
only once. This is a conservative criterion to ML-like languages use to handle
the interaction between polymorphism and imperative side-effects.

You can read about it in the FAQ:

Frank Atanassow, Information & Computing Sciences, Utrecht University
Padualaan 14, PO Box 80.089, 3508 TB Utrecht, Netherlands
Tel +31 (030) 253-3261 Fax +31 (030) 251-379
Bug reports:  FAQ:
To unsubscribe, mail  Archives: