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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Ada to Ada Translator ?
Date: Wed, 22 May 2019 15:16:35 -0500
Organization: JSA Research & Innovation
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"Optikos" <optikos@verizon.net> wrote in message 
news:1bb467ae-6e2c-4fef-aaab-556a8df71747@googlegroups.com...
...
>> There are (or at least were) a number of YACC
>> grammars for Ada floating around the web. And there's no difficulty in 
>> using
>> them...
>
>Aren't all the "number of YACC grammars for Ada floating around on the web"
>rather out-of-date for only Ada83 or Ada95?

Dunno. Since any computer science graduate (not to mention many others) can 
and probably has built a parser for some language, it's hardly that 
important to have one to reuse.

>If Patrick is proposing a tool that is capable of parsing Ada2005 or
>Ada2012 or Ada2020, then modernizing those out-of-date yacc
>grammars to the current era is of some degree of difficulty.

Maybe for self-taught programmers, but anyone who is familar with the basics 
of compiler construction can create/modify one very quickly. If it takes 
very long to understand someone else's parser, it's probably better to build 
your own. After all, the parser is probably less than 2% of a compiler or 
translator (even the lexer is likely to be harder).

>I reiterate:  Such an open-source Yacc grammar comprehensive of
>all variants of Ada (so that it could be a completely transparent
>front-end to GNAT) "would be an admirable accomplishment in its
>own right" as I originally stated.

That would take at most a week or two to create. The Janus/Ada grammar 
supports all of Ada 2012, and that only took about two weeks to build (most 
of the time being spent redoing the rest of the compiler to be able to 
detect/reject unimplemented stuff without crashing. the actual grammar work 
being only a day or so). It's just not that big of a deal. (The tool as a 
whole, of course, is a different story.)

                                          Randy.