🚀 go-pugleaf

In article <9310252122.AA26094@zeppelin.convex.com> helgaas@zeppelin.convex.com (Bjorn Helgaas) writes:
>> Besides using the undocumented "-aux-info" option of gcc, another
>> approach to building such a tool might be to start with yacc (or the GNU
>> equivalent) and an appropriate grammer for ANSI C (I've seen a few in the
>> public domain on various bulletin boards).  Then, you'd just have to
>> build action procedures for the appropriate nonterminal definitions to
>> capture the data you're looking for (function names, data types,
>> parameters, where-used stuff, etc.). 
>
>This would certainly be a plausible approach.  It is exactly what our
>current tool, cscope, does.  The problem is that this makes yet another
>tool that has to parse the C language.  Even though grammars are available,
>it is difficult to do it exactly right, especially when you want it to
>always match the compiler.

Quite so.  This is exactly the issue that Stallman (and others) miss when
they suggest creating totally separate front-ends to do source code
information-extraction jobs like this.

It's an important issue... especially with compilers which evolve as fast
as the GNU ones do.  That's why I built protoize the way I did (to use
the existing compiler to do the information collection) even over
Stallman's protestations that this was not the "right way" to build
such a tool.  (I note however that neither he not I have ever once
had to take the trouble to deal with a bug report stating that the
compiler and protoize have gotten out-of-sync with respect to the
languages they accept.)

>For example, cscope doesn't handle function
>definitions like this:
>
>    void f(void (*pf)()) {...}
>
>correctly.  The compiler already does all the parsing, and is more likely
>than anything else to do is correctly.

Exactly so.

-- 

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