warning at use of /c modifier without /g modifier

Message-ID: <20020328100440.22081.qmail@plover.com>

p4raw-id: //depot/perl@15579

diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 1323772..b9e9936 100644 (file)
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -555,6 +555,11 @@ the <FILEHANDLE> angle bracket operator.
 The command-line options -s and -F are now recognized on the shebang
 (#!) line.
 
+=item *
+
+Use of the C</c> match modifier without an accompanying C</g> modifier
+elicits a new warning: C<Use of /c modifier is meaningless without /g>.
+
 =back
 
 =head1 Modules and Pragmata

diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index d140b0a..3b3a71f 100644 (file)
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -3983,6 +3983,12 @@ returns no useful value.  See L<perlmod>.
 (D deprecated) You are now encouraged to use the explicitly quoted form
 if you wish to use an empty line as the terminator of the here-document.
 
+=item Use of /c modifier is meaningless without /g
+
+(W regexp) You used the /c modifier with a regex operand, but didn't
+use the /g modifier.  Currently, /c is meaningful only when /g is
+used.  (This may change in the future.)
+
 =item Use of *glob{FILEHANDLE} is deprecated
 
 (D deprecated) You are now encouraged to use the shorter *glob{IO} form

diff --git a/t/lib/warnings/toke b/t/lib/warnings/toke
index 01e31f8..af67277 100644 (file)
--- a/t/lib/warnings/toke
+++ b/t/lib/warnings/toke
@@ -103,7 +103,9 @@ toke.c      AOK
         $a =  0047777777777 ;
 
     dump() better written as CORE::dump()
-     
+
+    Use of /c modifier is meaningless without /g     
+
     Mandatory Warnings
     ------------------
     Use of "%s" without parentheses is ambiguous       [check_uni]
@@ -738,3 +740,22 @@ no warnings 'misc';
 "bar" =~ /\_/;
 EXPECT
 Unrecognized escape \q passed through at - line 4.
+########
+# toke.c
+# 20020328 mjd@plover.com at behest of jfriedl@yahoo.com
+use warnings 'regexp';
+"foo" =~ /foo/c;
+no warnings 'regexp';
+"foo" =~ /foo/c;
+EXPECT
+Use of /c modifier is meaningless without /g at - line 4.
+########
+# toke.c
+# 20020328 mjd@plover.com at behest of jfriedl@yahoo.com
+use warnings 'regexp';
+$_ = "ab" ; 
+s/ab/ab/c;
+no warnings 'regexp';
+s/ab/ab/c;
+EXPECT
+Use of /c modifier is meaningless without /g at - line 5.

diff --git a/toke.c b/toke.c
index 85ec1d1..7bc7661 100644 (file)
--- a/toke.c
+++ b/toke.c
@@ -26,6 +26,7 @@
 #define yylval PL_yylval
 
 static char ident_too_long[] = "Identifier too long";
+static char c_without_g[] = "Use of /c modifier is meaningless without /g";
 
 static void restore_rsfp(pTHX_ void *f);
 #ifndef PERL_NO_UTF16_FILTER
@@ -6284,6 +6285,13 @@ S_scan_pat(pTHX_ char *start, I32 type)
        while (*s && strchr("iogcmsx", *s))
            pmflag(&pm->op_pmflags,*s++);
     }
+    /* issue a warning if /c is specified,but /g is not */
+    if (ckWARN(WARN_REGEXP) && 
+        (pm->op_pmflags & PMf_CONTINUE) && !(pm->op_pmflags & PMf_GLOBAL))
+    {
+        Perl_warner(aTHX_ packWARN(WARN_REGEXP), c_without_g);
+    }
+
     pm->op_pmpermflags = pm->op_pmflags;
 
     PL_lex_op = (OP*)pm;
@@ -6332,6 +6340,13 @@ S_scan_subst(pTHX_ char *start)
            break;
     }
 
+    /* issue a warning if /c is specified,but /g is not */
+    if (ckWARN(WARN_REGEXP) &&
+        (pm->op_pmflags & PMf_CONTINUE) && !(pm->op_pmflags & PMf_GLOBAL))
+    {
+        Perl_warner(aTHX_ packWARN(WARN_REGEXP), c_without_g);
+    }
+
     if (es) {
        SV *repl;
        PL_sublex_info.super_bufptr = s;