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From: dewar@cs.nyu.edu (Robert Dewar)
Subject: Re: Call by reference vs. call by value
Date: 1996/07/21
Message-ID: <dewar.837995499@schonberg>#1/1
X-Deja-AN: 169435897
references: <31F10E50.726@egr.uri.edu> <DuwxnG.F2E@world.std.com>
organization: Courant Institute of Mathematical Sciences
newsgroups: comp.lang.ada
Date: 1996-07-21T00:00:00+00:00
List-Id: <comp.lang.ada>


Robert Duff said

"However, your suggested solution -- to always pass 'in' parameters by
reference -- is unacceptable from an efficiency point of view.  It means
you would have to copy huge amounts of data around when passing arrays
from one procedure to another to another to another."

OOPS, typo! he meant "allways pass 'in' parameters by copy"

incidentally, Algol-68 requires that the equivalent of in parameters
always be passed by copy (it really cannot be otherwise in the Algol-68
semantic framework). However the only really successful implementation
of Algol-68 (Ian Currie's Algol-68R), completely ignored this and passed
all arrays by reference anyway -- he never got ONE complaint from a user
(although see the 1968 Munich proceedings to see him being denounced by
the Algol-68 cognoscenti -- Barry Mailloux accused him of heresy, and
reminded him that there was only one source of truth -- the Algol 68
report :-)