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From: Paul Graham <pgraham@cadence.com>
Subject: Re: No Go To's Forever!
Date: 2000/03/23
Message-ID: <38DA2F9C.BAFF8C60@cadence.com>#1/1
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References: <38D7B41D.B3494C6A@lmco.com> <8b8m2e$8201@news.cis.okstate.edu>
 <8b9fk3$l18$1@nnrp1.deja.com> <38D8DFC2.778826FB@cadence.com>
 <8barci$4ks$1@nnrp1.deja.com> <38D9233B.D51B16A3@cadence.com>
 <8bbsl4$ani$1@nnrp1.deja.com> <8bd9ve$r1c$1@nnrp1.deja.com>
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Organization: Cadence Design Systems
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Newsgroups: comp.lang.ada
Date: 2000-03-23T00:00:00+00:00
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Ted Dennison wrote:
> 
> In article <8bbsl4$ani$1@nnrp1.deja.com>,
> Robert Dewar <robert_dewar@my-deja.com> wrote:
> > In article <38D9233B.D51B16A3@cadence.com>,
> >
> > But surely you would enforce this usage with a tool. There are
> > no general defences against sufficiently incompetent
> > maintainers.
> 
> A tool? How would such a tool be written? It looks to me like you'd need
> an Ada parser to hook it to. Not everyone has the ability or permission
> to hack stuff like this into their compiler. Perhaps ASIS could help,
> but not every compiler supports ASIS.

I was wondering the same thing.  I suppose AdaLint could issue a warning
for any goto statement within a loop that jumped to a label within the
loop, unless the label was immediately followed by a null statement and
an end loop.

Indeed, many of Ada's features address the "incompetent maintainer"
problem.  For instance, the problem of maintaining an if statement in C
if there is no brace:

    if (condition)
        stmt1;
        stmt2;

Here the maintainer thinks he's adding stmt2 to the then-clause of the
if statement. The Ada if syntax prevents this from happening.

Paul