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From: Robert Dewar <robert_dewar@my-deja.com>
Subject: Re: No Go To's Forever!
Date: 2000/03/22
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In article <8b8m2e$8201@news.cis.okstate.edu>,
  dstarner98@aasaa.ofe.org wrote:

> The GNAT sources contain 300-400 goto statements and
> a brief glance at parts shows that the goto statements
> are highly readable.

It's actually quite instructive to look through these goto
statements.

About 60% are in the finite state machine that is part of the
SPITBOL pattern matching unit. I have always felt that gotos
are a very natural representation of the arcs of a finite
state machine, and I invite people to look at the code of
g-spipat.adb to see if you agree :-)

Another section are for the finite state machine in the scanner.

Another big bunch are continue gotos. Ada lacks a continue
statement, and thus this facility must be simulated with a goto
as in

   loop

    if ... then goto Continue;

   <<Continue>> null;
   end loop;

This is actually quite a structured use of goto

There are only about 8 other instances of gotos in the
several hundred thousand lines of sources.


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