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From: tmb@ai.mit.edu (Thomas M. Breuel)
Newsgroups: comp.lang.functional
Subject: Re: A question about types in ML
Message-ID: <11943@life.ai.mit.edu>
Date: 18 Nov 90 22:26:44 GMT
References: <fraser.658398987@melomys> <4906@rex.cs.tulane.edu> 	<2215@opal.cs.tu-berlin.de> <4971@rex.cs.tulane.edu> 	<11901@life.ai.mit.edu> <PETERSON-JOHN.90Nov15223106@object.cs.yale.edu> <2236@opal.cs.tu-berlin.de>
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In article <2236@opal.cs.tu-berlin.de>, wg@opal.cs.tu-berlin.de (Wolfgang Grieskamp) writes:
|> peterson-john@cs.yale.edu (John C. Peterson) writes:
|> 
|>   >Regarding typing in Common Lisp & ML, it is incorrect to say that
|>   >Common Lisp lacks types; type declarations in CL are actually far more
|>   >general than those in ML.  What Common Lisp lacks is any sort of well
|>   >defined type inference, a major deficiency.
|> 
|> As i remember from a short afair with LISP some years ago, type 
|> declarations in CL are always monomorphic: no parametric 
|> polymorphy, no type variables. 
|> 
|> Hence the "far more generalicity" you mentioned is to omit types? 

(deftype halting-function ()
   '(and function (satisfies halting-p)))