From: stdsee01@pip.shsu.edu (Road Pilot)
Subject: Re: Syntax question
Date: 11 Mar 1995 15:44:14 -0600
Date: 1995-03-11T15:44:14-06:00 [thread overview]
Message-ID: <3jt5je$d0u@pip.shsu.edu> (raw)
In-Reply-To: 3jrt1m$9rk@erinews.ericsson.se
Geoffrey Hollingworth (etlghh@garbo.ericsson.se) wrote:
: Hi
:
: I am currently researching into real time languages and hope
: you ada experts can explain something to me. I apologise for
: my lack of knowledge in ada.
: When binding formal parameters with actual parameters the '=>'
: operator is used, irrespective of whether the formal parameter
: is declared as IN, INOUT or OUT. Is there a reason for this ?
: If I proposed an alternative syntax where "=>" indicated the FP
: was an IN parameter, "<=" to indicate an OUT parameter and "<=>"
: to indicate an INOUT.
: Then the caller of the procedure/function would have explicitly
: had to understand to direction of the parameters and at the same
: time increased the readability of his/her code.
: Is there a fundamental flaw in this line of thinking ?
: Does ada manage this problem via a different mechanism ?
:
: Any information, historical or otherwise, would be a great help
: to me and greatly appreciated.
:
: thanks
:
: /geoff
Well, the arrow symbol "=>" is not meant to imply direction. It is used in
the case statement (ex: WHEN choice => statement) and in aggregate assingments
as well (ex: initializing specific cells of an array without multiple index
references). This is all in contrast to positional reference. In your a
function/procedure call, the use of the arrow notation is completely
optional. In some cases of multiple parameters, it makes it easier to keep
them straight. I like to use them mainly because it avoids confusion.
Like so:
procedure insert( list : in out integer; item : in integer ) is
insert( 2, 4 ); OR insert (list=>2, item=>4);
either way will work.
I don't know if this helps any or just confuses more, but I guess the main
thing is that the arrow is more like a placeholder or referencing tool and
is not meant to imply direction.
Sloaner
stdsee01@pip.shsu.edu
next prev parent reply other threads:[~1995-03-11 21:44 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
1995-03-11 10:12 Syntax question Geoffrey Hollingworth
1995-03-11 15:16 ` Robert A Duff
1995-03-11 20:45 ` Michael Feldman
1995-03-15 23:29 ` David Kusuda
1995-03-16 2:25 ` David Weller
1995-03-16 14:44 ` Spencer Allain
1995-03-19 1:04 ` Robert Dewar
1995-03-16 9:19 ` Fred J. McCall
1995-03-17 5:44 ` Niklas Holsti
1995-03-19 20:53 ` Robert Dewar
1995-03-11 21:44 ` Road Pilot [this message]
1995-03-23 13:07 ` Bob Collins
1995-03-24 1:11 ` Kevin F. Quinn
1995-03-27 14:19 ` Norman H. Cohen
1995-03-13 4:43 ` Keith Thompson
1995-03-16 20:37 ` Norman H. Cohen
1995-03-21 0:51 ` Robert Dewar
1995-03-16 19:20 ` Adam Beneschan
-- strict thread matches above, loose matches on Subject: below --
2001-07-05 17:58 Syntax Question Robby Simpson
2001-07-05 18:32 ` Marin David Condic
2001-07-05 18:38 ` Robby Simpson
2001-07-05 19:09 ` Ted Dennison
2001-07-05 20:14 ` Robby Simpson
2001-07-05 21:44 ` Robert Dewar
2001-07-09 12:39 ` Robby Simpson
[not found] <Cx6pG3.IEp@ucc.su.oz.au>
1994-10-05 14:20 ` Syntax question Tucker Taft
[not found] ` <36ui0u$4dg@gnat.cs.nyu.edu>
1994-10-06 0:04 ` David Weller
1994-10-05 5:19 Adrian Cho
1994-10-05 11:52 ` Robert Dewar
1994-10-05 17:19 ` Norman H. Cohen
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