Looking at the Camel book, 3rd edn., table 5-1 on page 150, the entry for /s says "Let . match newline ... " which sort of implies that /m doesn't. So it is the treatment of the "." metacharacter that changes between the two. This with no modifying flag also matches

($span_d) = $str =~ /(\d\d\w+\s\w+\d\d/;

[download]

This might imply that the default behaviour of m/.../ with no modifying flag is the same as m/.../m. I will delve into the documentation when I get a chance.

Cheers,

Johngg

Update:

This passage is in the "perlre" manual page

...
     m   Treat string as multiple lines.  That is, change "^" and
         "$" from matching the start or end of the string to
         matching the start or end of any line anywhere within
         the string.

     s   Treat string as single line.  That is, change "." to
         match any character whatsoever, even a newline, which
         normally it would not match.

         The "/s" and "/m" modifiers both override the $*
         setting.  That is, no matter what $* contains, "/s"
         without "/m" will force "^" to match only at the
         beginning of the string and "$" to match only at the end
         (or just before a newline at the end) of the string.
         Together, as /ms, they let the "." match any character
         whatsoever, while still allowing "^" and "$" to match,
         respectively, just after and just before newlines within
         the string.

...

perl v5.8.4          Last change: 2004-01-17                    1

[download]

In reply to Re^4: Passing variables into regular expressions by johngg
in thread Passing variables into regular expressions by wanderer

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.