bug#5055: 23.1; etags of perl "use constant"

[Kevin Ryde]

It'd be good if etags recognised perl constants like

    use constant FOO => 123;

which defines a subroutine called FOO, basically the same as if you
wrote

    sub FOO () { return 123 }


"constant::defer" in the diff below is one of my things.  Is it too
cheeky to slip that in?  It's on cpan, but probably used only by me as
yet :-).


2009-11-27  Kevin Ryde  <user42@zip.com.au>

        * etags.c (Perl_functions): Tag "use constant" subs too.

        * maintaining.texi (Tag Syntax): Add Perl "use constant".

Index: lib-src/etags.c
===================================================================
RCS file: /sources/emacs/emacs/lib-src/etags.c,v
retrieving revision 3.93
diff -u -r3.93 etags.c
--- lib-src/etags.c     23 Nov 2009 09:51:06 -0000      3.93
+++ lib-src/etags.c     27 Nov 2009 00:05:52 -0000
@@ -4388,6 +4388,7 @@
 /*
  * Perl support
  * Perl sub names: /^sub[ \t\n]+[^ \t\n{]+/
+ *                 /^use constant[ \t\n]+[^ \t\n{=,;]+/
  * Perl variable names: /^(my|local).../
  * Original code by Bart Robinson <lomew@cs.utah.edu> (1995)
  * Additions by Michael Ernst <mernst@alum.mit.edu> (1997)
@@ -4411,9 +4412,9 @@
        }
       else if (LOOKING_AT (cp, "sub"))
        {
-         char *pos;
-         char *sp = cp;
-
+         char *pos, *sp;
+       subr:
+         sp = cp;
          while (!notinname (*cp))
            cp++;
          if (cp == sp)
@@ -4436,6 +4437,21 @@
                        lb.buffer, cp - lb.buffer + 1, lineno, linecharno);
              free (name);
            }
+       }
+      else if (LOOKING_AT (cp, "use constant")
+              || LOOKING_AT (cp, "use constant::defer"))
+       {
+         /* For hash style multi-constant like
+          *     use constant { FOO => 123,
+          *                    BAR => 456 };
+          * only the first FOO is picked up.  Parsing across the value
+          * expressions would be difficult in general, due to possible nested
+          * hashes, here-documents, etc.  Maybe simple values could be
+          * handled.
+          */
+         if (*cp == '{')
+           cp = skip_spaces (cp+1);
+         goto subr;
        }
        else if (globals)       /* only if we are tagging global vars */
        {
Index: doc/emacs/maintaining.texi
===================================================================
RCS file: /sources/emacs/emacs/doc/emacs/maintaining.texi,v
retrieving revision 1.22
diff -u -r1.22 maintaining.texi
--- doc/emacs/maintaining.texi  11 Jul 2009 02:49:07 -0000      1.22
+++ doc/emacs/maintaining.texi  27 Nov 2009 00:06:02 -0000
@@ -1681,7 +1681,8 @@
 
 @item
 In Perl code, the tags are the packages, subroutines and variables
-defined by the @code{package}, @code{sub}, @code{my} and @code{local}
+defined by the @code{package}, @code{sub}, @code{use constant},
+@code{my} and @code{local}
 keywords.  Use @samp{--globals} if you want to tag global variables.
 Tags for subroutines are named @samp{@var{package}::@var{sub}}.  The
 name for subroutines defined in the default package is


In GNU Emacs 23.1.1 (i486-pc-linux-gnu, GTK+ Version 2.16.5)
 of 2009-09-14 on raven, modified by Debian
configured using `configure  '--build=i486-linux-gnu' '--host=i486-linux-gnu' 
'--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' 
'--localstatedir=/var/lib' '--infodir=/usr/share/info' 
'--mandir=/usr/share/man' '--with-pop=yes' 
'--enable-locallisppath=/etc/emacs23:/etc/emacs:/usr/local/share/emacs/23.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.1/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.1/leim'
 '--with-x=yes' '--with-x-toolkit=gtk' '--with-toolkit-scroll-bars' 
'build_alias=i486-linux-gnu' 'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -g 
-O2' 'LDFLAGS=-g' 'CPPFLAGS=''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_AU
  value of $XMODIFIERS: nil
  locale-coding-system: iso-latin-1-unix
  default-enable-multibyte-characters: t