RE: Problems with Let Polymorphism and CT-Proj

From: Rui Shi (shearer@cs.bu.edu)
Date: Mon Nov 27 2006 - 16:59:12 EST 

Return-Path: <shearer@cs.bu.edu>
X-Spam-HitLevel: 
X-Spam-DCC: INFN-TO: cs3.bu.edu 1233; Body=1 Fuz1=1 Fuz2=1
X-Spam-Checker-Version: SpamAssassin 3.1.0 (2005-09-13) on cs3.bu.edu
X-Spam-Level: 
X-Spam-Status: No, score=-4.4 required=10.0 tests=ALL_TRUSTED,AWL,BAYES_00  autolearn=ham version=3.1.0
X-Spam-Pyzor: 
Received: from SHEARERSHOT (cs-dhcp150 [128.197.10.150]) (authenticated bits=0) by cs3.bu.edu (8.13.6/8.13.6) with ESMTP id kARLx9YR012904; Mon, 27 Nov 2006 16:59:14 -0500
Message-Id: <200611272159.kARLx9YR012904@cs3.bu.edu>
From: "Rui Shi" <shearer@cs.bu.edu>
To: <samepst@cs.bu.edu>
Cc: <cs520@cs.bu.edu>
Subject: RE: Problems with Let Polymorphism and CT-Proj
Date: Mon, 27 Nov 2006 16:59:12 -0500
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-Mailer: Microsoft Office Outlook, Build 11.0.5510
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2962
Thread-Index: AccSbjxBLED2NpvxTkGkVei7a+1NgQAALbsQ
In-Reply-To: <11633.71.192.166.44.1164664306.squirrel@cs-squirrelmail.bu.edu>
X-Clamav-Status: No
Status: RO
Content-Length: 690
X-UID: 66
X-Keywords:

After solving the current constraints, if you still can't know it is a
Tptup. Just issue a type error. That is exactly the case in SML and Ocaml.

Rui

-----Original Message-----
From: samepst@cs.bu.edu [mailto:samepst@cs.bu.edu]
Sent: Monday, November 27, 2006 4:52 PM
To: cs520@cs.bu.edu
Subject: Problems with Let Polymorphism and CT-Proj

I have doubts whether solving all the current constraints whenever a
projection is found will work, especially with the Let-Polymorphism. Here is
a typed term which would break my typechecker:

let f = lam x => lam y => (x y).2
in f (lam z=> (z,z)) 5

Can it be assumed that these special cases will not be tested?

Thank you,
-Sam Epstein

This archive was generated by hypermail 2b29 : Thu Dec 14 2006 - 16:31:59 EST