Re: [Ctags] Exuberant Ctags problem with extern ... INIT

[James A P. <Jam...@ae...>]

> On Wed, 14 Nov 2001, James A Paget wrote:
>
> > ...in the application I am working on, Exuberant Ctags fails to
> > find a few of the tags.  The problem occurs in files such as
> > include.h, listed below:
> >
> > #ifdef ALLOCATE
> > #define extern
> > #define INIT(A) = (A)
> > #else
> > #define INIT(A)
> > #endif
> >
> > extern int unfound INIT(0);
> >
> > I have tried to get ctags to include unfound, but to no avail.  Here
are
> > two approaches I tried, neither of which resulted in a tag for
"unfound":
> >
> > ctags -f - -I INIT== include.h

> This works for me. I do not know why this does not work for you.
> I put the above text exactly into a file and ran it exactly as you
> indicated.

I've tried this using Exuberant Ctags 5.1 on Windows 2000 and it still
does not work.  I'm attaching a zip file with include.h,
tags1.bat ("ctags -f output1 -I INIT== include.h"), and output1 so you
can reproduce the situation exactly.  There are 3 tags, but none for
"unfound".

(See attached file: tags.zip)

> There are 3 other possible ways to make this work:
>
> 1.  Tags for external variable declarations are not included in the
>     output by default. You can change this default by adding the
>     option "--c++-types=+x"
>
> 2.  Make ctags ignore the "extern" by adding the option "-I extern".

These are no help; I want a tag only if "extern" appears with "INIT".

> 3.  The "INIT(0);" call throws off the parser. To make the parser
>     ignore it, use the option "-I INIT+".

Still no tag for "unfound"; see tags2.bat and output2, included in the
zip file above.

>
> > ctags -f - -n "--regex-C++=/extern\(.*\)INIT\(.*\)/\1 = \2/" include.h
>
> This does not work because the regular expressions that ctags uses
> are POSIX "extended regular expressions", which already treat "("
> and ")" as metacharacters; by escaping them, you were indicating
> they should be treated as literals. Removing these causes the line
> to be matched:
>
>
>    ctags -f - -n "--regex-C++=/extern(.*)INIT(.*)/\1 = \2/" include.h

Where can I find documentation for the precise syntax for POSIX
"extended regular expressions"?  Running "man -s 5 regex" on Solaris
2.6 led me to believe that "(" is a normal character and "\(" is
the metacharacter.  This is also true for regular expressions in vim.

> However, this uncovered a bug in the regex handling in ctags, where
> the \2 contained the terminating newline and messed up the tag file.
> I have fixed this for the next minor release.

This seems to work fine for me in Windows 2000 with ctags 5.1.  See
tags3.bat and output3 in the zip file.

-- Jim Paget