Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!mcnc!rutgers!sri-spam!ames!ptsfa!ihnp4!chinet!nucsrl!gore From: gore@nucsrl.UUCP (Jacob Gore) Newsgroups: comp.lang.pascal Subject: Re: Pointer problem ? Message-ID: <4020003@nucsrl.UUCP> Date: Sat, 25-Jul-87 17:18:42 EDT Article-I.D.: nucsrl.4020003 Posted: Sat Jul 25 17:18:42 1987 Date-Received: Sun, 26-Jul-87 20:58:00 EDT References: <254@askja.UUCP> Organization: Northwestern U, Evanston IL, USA Lines: 19 / nucsrl:comp.lang.pascal / dyck@sfu_halley.cs.sfu / 12:57 am Jul 25, 1987 / >program t; | Even though the first two type definitions have the same >type | RHS, section 6.4.1 of the Standard says that each > p1 = ^p1; | occurrence of a new-type (e.g. each of the two > p2 = ^p1; | occurrences of ^p1) shall denote a type that is distinct > p3 = ^p2; | from [the type denoted by] any other new-type. So p1 and >var p : p1; | p2 (and p3) denote distinct types. When was "the Standard" established? I don't think Wirth initially specified whether Pascal used structure-compatible or name-compatible types. I am well (and painfully) aware that the VMS Pascal compiler uses structure-compatibility, but I would not be surprised if that compiler predates "the Standard." They can't "fix" it now, since they need to maintain backward compatibility with previous versions of the compiler. To many older programs would be broken if they did. Jacob Gore gore@EECS.NWU.Edu Northwestern Univ., EECS Dept. {gargoyle,ihnp4,chinet}!nucsrl!gore