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From: ok@goanna.cs.rmit.edu.au (Richard A. O'Keefe)
Subject: Re: Modest proposal, 2 of 3
Date: 1996/11/28
Message-ID: <57ivs0$hr6$1@goanna.cs.rmit.edu.au>#1/1
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references: <575ag6$rt6@netline-fddi.jpl.nasa.gov>
 <3299FA03.5A1D@watson.ibm.com>
organization: Comp Sci, RMIT, Melbourne, Australia
nntp-posting-user: ok
newsgroups: comp.lang.ada
Date: 1996-11-28T00:00:00+00:00
List-Id: <comp.lang.ada>


>Van Snyder wrote:
> PROPOSAL for next standardization of Ada
> 
> Allow objects to be declared in the public part of a package
> specification with mode "out".  The meaning is that clients of the
> package can reference the variable, but can't store into it.

I note that exporting a function instead has a big advantage:
functions are overloaded, variables aren't.  This is only an
issue to people who use 'use', of course.

I note another benefit of using access functions instead, which
is that if you wonder whether the "variable" actually _is_ being
used outside the package, you can compile for debugging and put
a breakpoint on it, or you can use a profiler like gprof.
A cross-reference would show you _static_ = potential uses only,
a debugger or profiler can show you _actual_ uses.  There's no
reason why profilers _couldn't_ could variable accesses, but none
that I have seen actually does so.

-- 
Fear most of all to be in error.	-- Kierkegaard, quoting Socrates.
Richard A. O'Keefe; http://www.cs.rmit.edu.au/%7Eok; RMIT Comp.Sci.