* lib-src/etags.c (Perl_functions): Support "use constant".

* doc/emacs/maintaining.texi (Tag Syntax): Mention Perl's "use constant".

Fixes: debbugs:5055

2 files changed, 22 insertions, 3 deletions

diff --git a/lib-src/ChangeLog b/lib-src/ChangeLog
index a74d4b90b9f..294661a6cb3 100644
--- a/lib-src/ChangeLog
+++ b/lib-src/ChangeLog
@@ -1,3 +1,7 @@
+2012-12-01  Kevin Ryde  <user42@zip.com.au>
+
+        * etags.c (Perl_functions): Support "use constant" (Bug#5055).
+
 2012-11-27  Paul Eggert  <eggert@cs.ucla.edu>
 
         Assume POSIX 1003.1-1988 or later for errno.h (Bug#12968).
diff --git a/lib-src/etags.c b/lib-src/etags.c
index b6af17b8edf..ec185c9819f 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -4269,6 +4269,7 @@ Asm_labels (FILE *inf)
 /*
  * 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)
@@ -4291,9 +4292,10 @@ Perl_functions (FILE *inf)
         }
       else if (LOOKING_AT (cp, "sub"))
         {
-          char *pos;
-          char *sp = cp;
+          char *pos, *sp;
 
+        subr:
+          sp = cp;
           while (!notinname (*cp))
             cp++;
           if (cp == sp)
@@ -4316,8 +4318,21 @@ Perl_functions (FILE *inf)
                         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.  */
+          if (*cp == '{')
+            cp = skip_spaces (cp+1);
+          goto subr;
         }
-       else if (globals)        /* only if we are tagging global vars */
+      else if (globals) /* only if we are tagging global vars */
         {
           /* Skip a qualifier, if any. */
           bool qual = LOOKING_AT (cp, "my") || LOOKING_AT (cp, "local");