Article View: comp.lang.misc
Article #935Re: Relationship between C and C++
From: David Gudeman
Date: Thu, 22 Mar 1990 07:21
Date: Thu, 22 Mar 1990 07:21
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1590 bytes
In article <4869@vanuata.cs.glasgow.ac.uk> jack@cs.glasgow.ac.uk (Jack Campin) writes: >[about C style pointers] >Thirdly, the aliasing it enables is a semantic mess. If anyone claims >different, let's see your denotational model of ANSI C. Sure, but first show me your denotational model of Ada. Seriously though, there is nothing unusually complex about the semantics of pointers. In fact, the traditional model of stores uses pointers (usually called "locations") anyway. The only things that have to be added are (1) a new data type (pointer) that includes, not only a location, but also an indication of what the pointer points at and any index constraints, and (2) operations on the new data type. One workable implementations is defining a pointer as a triple, and defining operators to do the appropriate range checks. Incrementing a pointer past the bounds of its array is an undefined operation. The description is not simple, but then almost no substantial programming language feature is simple to describe mathematically. -- David Gudeman Department of Computer Science The University of Arizona gudeman@cs.arizona.edu Tucson, AZ 85721 noao!arizona!gudeman
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!elroy.jpl.nasa.gov!ames!ig!arizona!gudeman From: gudeman@cs.arizona.edu (David Gudeman) Newsgroups: comp.lang.misc Subject: Re: Relationship between C and C++ Message-ID: <19255@megaron.cs.arizona.edu> Date: 22 Mar 90 07:21:55 GMT Organization: U of Arizona CS Dept, Tucson Lines: 24