Re: Bug Report (Feature request?) etags (GNU Emacs 21.1)

[David Masterson]

>>>>> Francesco Potorti` writes:

David> words, would etags wind up generating the same reference twice
David> (once from the generated file and once from the original)?
   
>> etags will already do this if you run it on parse.y and parse.c.
>> I've always found this a bit annoying.  Usually I use some Makefile
>> rule I didn't write to generate TAGS.  So parse.c is included, but
>> I don't want it, since I never want to edit it.  In this scenario
>> it would be convenient if etags ignored the generated file.

> I suppose you mean a rule like this:

> if etags finds a #line directive in file X pointing to file Y, and
> if file Y is given on the command line, then ignore file X.

No.  It would have to go further than that.  Because of limitations in
the shell command line, file X may not be on the etags command line.

> Maybe this would better be handled by not giving file X to etags to
> parse.  Should etags correct this common makefile error?  By the
> way, it wouldn't be so easy, as currently etags processes files
> independently of each other, in sequence.

Actually, it should be easy.  Include an option "--ignore-gen-files"
which means that etags should ignore any generated file.  A parameter
to this option would be a regexp pattern that could be used to check a
line to see if the file is generated (default would be "#line").  This
option should also be settable as an environment variable (because
some people have to deal with Makefiles that they cannot change).

> Going back to the original question, what happens if you give to
> etags the original .web file, instead of the .c produced from it?

Again, in large projects, you might run a recursive etags in a
directory and accidently pick up both.  Given the size of the project,
it may be sometime before you realize it.  It can be worked around,
but it can be annoying.

-- 
David Masterson                dmaster AT synopsys DOT com
Sr. R&D Engineer               Synopsys, Inc.
Software Engineering           Sunnyvale, CA