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Date: Fri, 08 Nov 2002 20:01:48 +0800
From: Adrian Hoe <mailbox@*nospam*adrianhoe.com>
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Subject: Re: Let's change semantics of "use type"
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Date: 2002-11-08T20:01:48+08:00
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Victor Porton wrote:

> I am suggesting (for the next Standard) to change the semantics of "use
> type" so that it would make visible not only primitive _operators_, but
> all primitive _operations_.
> 
> It seems (at the first glance) that changing Standard such the way would
> not make any correct program incorrect. (However it would make some current
> programs not compilable. If this is too bad, it can be instead denoted as
> "use all type;" for using all operations, not only operators.)
> 
> The rationale is that this is a convenient way for dealing with a type 
> imported from a package without the need of many rename directives.  These
> directives may make a long list and are "dirty" for both writing and
> reading. (Reading this list one may not understand for exactly what is
> present an item of the list and so not know (without experiment with a
> compiler) whether this item can be removed without breaking the program.
> So in certain sense the current Ada is not perfectly readable.) With "use
> all type" programmers will less tend to write multi-level designators
> which are both unreadable (especially when there are several such
> designators in an expression) and error-prone as one may forget y in
> x.y.z (mistakedly writing x.z) and get wrong behavior of the program.
> 


Without the rename directives, the program will be difficult to 
understand. With your suggestion of "use all type" may be good for 
short programs but not "large" program.

I would prefer current standards for a typical large with hundreds 
thousand lines of code (if not million) will be easily understood.
-- 
type Dmitry is new Adrian;           -- Adrian Hoe
                                      -- http://adrianhoe.com
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