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From: Pierre Weis <Pierre.Weis@inria.fr>
Message-Id: <199901211532.QAA18132@pauillac.inria.fr>
Subject: Re: monomorphism is ... ?
To: tm1@cise.npl.co.uk (Toby Moth)
Date: Thu, 21 Jan 1999 16:32:00 +0100 (MET)
Cc: caml-list@inria.fr
In-Reply-To: <199901211150.LAA06705@squall.cise.npl.co.uk> from "Toby Moth" at Jan 21, 99 11:50:29 am
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> Am I right in thinking that the following holds ?
> 
> polymorphic  = has type 'a  = for all
> monomorphic  = has type '_a = exists
> 
> Here '=' stands for 'equal in spirit'.
> 
> 
> Toby Moth

Yes you are 'right in spirit': more precisely '_a means an unknown
type, that should be precised by further constraints or computations
(as are unknowns in math). There is no quantifier in a type with '_a,
as opposed to existential types (type scheme with existential
quantifier in fact).

Pierre Weis

INRIA, Projet Cristal, Pierre.Weis@inria.fr, http://cristal.inria.fr/~weis/