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From: bertrand@eiffel.UUCP (Bertrand Meyer)
Newsgroups: comp.object
Subject: Re: value semantic versus reference semantic
Message-ID: <575@eiffel.UUCP>
Date: 18 May 91 19:21:45 GMT
References: <68780001@hpcupt1.cup.hp.com> <1991May14.093053.3017@jyu.fi>
Organization: Interactive Software Engineering, Santa Barbara CA
Lines: 18

From <1991May14.093053.3017@jyu.fi> by sakkinen@jyu.fi (Markku Sakkinen):

> note that almost all OOPL's offer only reference semantics
> for objects.  C++ is one of the refreshing exceptions.

There are two categories of Eiffel types: reference types and expanded
types. For assignment as well as argument passing (collectively
called ``reattachment operations''), the former follow
reference semantics, the latter follow copy semantics. Predefined
expanded types include the arithmetic types INTEGER etc.; but
given a class C, you can define the new expanded type `expanded C',
or `expanded C [T, ...]' if C is generic.  In other words, programmers
get to control the exact semantics of reattachment - reference
assignment or copy. 
-- 
-- Bertrand Meyer
Interactive Software Engineering Inc., Santa Barbara
bertrand@eiffel.uucp