Re: mysterious regexp syntax

[Tux]

$ man perlop
:
:
               If "/" is the delimiter then the initial "m" is optiona
+l.  With
               the "m" you can use any pair of non-whitespace (ASCII)
               characters as delimiters.  This is particularly useful 
+for
               matching path names that contain "/", to avoid LTS (lea
+ning
               toothpick syndrome).  If "?" is the delimiter, then a m
+atch-
               only-once rule applies, described in "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 "m".
:
:
       m?PATTERN?msixpodualgc
       ?PATTERN?msixpodualgc
               This is just like the "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 "m??"  patterns local to the current pa
+ckage
               are reset.

[grizzley]

Ahhhh... So possibility to omit 'm' remains in case of '?' delimiter. That is what I've been missing.

# perl -le '$_="abc"; print 1 if ?b?'

Thanks for clarification!

[Athanasius]

But note the following, from perl5140delta:

?PATTERN? (without the initial m) has been deprecated and now produces a warning. This is to allow future use of ? in new operators. The match-once functionality is still available as m?PATTERN?.

So with v5.14.4, I get:

22:39 >perl -le "$_ = qq[abc]; print 1 if ?b?;"
Use of ?PATTERN? without explicit operator is deprecated at -e line 1.
1

22:39 >

Hope that helps,