From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: *
X-Spam-Status: No, score=1.8 required=5.0 tests=BAYES_20,FROM_STARTS_WITH_NUMS,
	INVALID_DATE autolearn=no autolearn_force=no version=3.4.4
Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!mit-eddie!ll-xn!ames!aurora!labrea!jade!ucbvax!NAVPGS.BITNET!4526P
From: 4526P@NAVPGS.BITNET ("LT Scott A. Norton, USN")
Newsgroups: comp.lang.ada
Subject: Re: using <subprogram>'address for callback
Message-ID: <8709162054.AA24871@ucbvax.Berkeley.EDU>
Date: Wed, 16-Sep-87 14:55:00 EDT
Article-I.D.: ucbvax.8709162054.AA24871
Posted: Wed Sep 16 14:55:00 1987
Date-Received: Sat, 19-Sep-87 11:45:25 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
List-Id: <comp.lang.ada>

( Please excuse me if I have a Pascal accent; I still can't write
Ada without the book open in my lap. )

The disscussion on X-windows, particularly callbacks, has
reawakend my interest in one of the design decisions from
Steelman.  The particular feature of Ada that caught my eye, when
I first was learning the language, was that a procedure could not
have a function or another procedure as a formal parameter.  I
don't think that "integrate( f, a, b )" is poor software
engineering, but you can't do that directly in Ada.  The Ada
solution I saw in one text for integrating a function involved
generics, but that seem kludgy to me.  So, I'm asking:

 1. Why does Ada not permit functions as formal parameters?

 2. Is there some other clean way to model functionals ( functions of
    functions ) besides instantionating a generic for each pair of
    functional and its argument function?

I realize that sometimes, a programming model that works well in
one context produces serious inconsistancies in another.  And so,
we don't see Algol-60 call by name anymore.

LT Scott A. Norton, USN
Naval Postgraduate School
Monterey, CA 93943-5018
4526P@NavPGS.BITNET