Deprecate ?PATTERN? without explicit m operator

Deprecate ?PATTERN?, recommending the equivalent m?PATTERN? syntax, in
order to eventually allow the question mark to be used in new operators
that would currently be ambiguous.

(With minor reconciliation edits by David Golden)

Signed-off-by: David Golden <dagolden@cpan.org>

1 files changed, 17 insertions, 12 deletions

diff --git a/pod/perlop.pod b/pod/perlop.pod
index 1b258c0926..b31b9bec99 100644
--- a/pod/perlop.pod
+++ b/pod/perlop.pod
@@ -1357,11 +1357,12 @@ process modifiers are available:
  g  Match globally, i.e., find all occurrences.
  c  Do not reset search position on a failed match when /g is in effect.
 
-If "/" is the delimiter then the initial C<m> is optional.  With the
-C<m> you can use any pair of non-whitespace characters as delimiters.
-This is particularly useful for matching path names that contain "/",
-to avoid LTS (leaning toothpick syndrome).  If "?" is the delimiter,
-then the match-only-once rule of C<m?PATTERN?> applies (see below).
+If "/" is the delimiter then the initial C<m> is optional.  With the C<m>
+you can use any pair of non-whitespace characters
+as delimiters.  This is particularly useful for matching path names
+that contain "/", to avoid LTS (leaning toothpick syndrome).  If "?" is
+the delimiter, then a match-only-once rule applies,
+described in C<m?PATTERN?> below.
 If "'" is the delimiter, no interpolation is performed on the PATTERN.
 When using a character valid in an identifier, whitespace is required
 after the C<m>.
@@ -1526,10 +1527,10 @@ Here is the output (split into several lines):
 	lowercase line-noise MiXeD line-noise. That's all!
 
 =item m?PATTERN?
-X<?>
+X<?> X<operator, match-once>
 
-This is just like the C<m/pattern/> search, except that it matches only
-once between calls to the reset() operator.  This is a useful
+This is just like the C<m/PATTERN/> search, except that it matches
+only once between calls to the reset() operator.  This is a useful
 optimization when you want to see only the first occurrence of
 something in each file of a set of files, for instance.  Only C<m??>
 patterns local to the current package are reset.
@@ -1539,12 +1540,16 @@ patterns local to the current package are reset.
 			    # blank line between header and body
 	}
     } continue {
-	reset if eof;	    # clear ?? status for next file
+	reset if eof;	    # clear m?? status for next file
     }
 
-The use of C<?PATTERN?> without a leading "m" is vaguely deprecated,
-which means it just might possibly be removed in some distant future
-version of Perl, perhaps somewhere around the year 2168.
+The match-once behaviour is controlled by the match delimiter being
+C<?>; with any other delimiter this is the normal C<m//> operator.  
+
+For historical reasons, the leading C<m> in C<m?PATTERN?> is optional,
+but the resulting C<?PATTERN?> syntax is deprecated, will warn on
+usage and may be removed from a future stable release of Perl without
+notice.
 
 =item s/PATTERN/REPLACEMENT/msixpogcer
 X<substitute> X<substitution> X<replace> X<regexp, replace>