in reply to Re^3: Internal representation of qr// compiled regular expressions
in thread Internal representation of qr// compiled regular expressions

Wow, has it really been nearly five years?!

So, is the mg_obj member in a different place from where normal representations are stored for scalars? Point is, I guess, is that it's done in a totally different way than just blessing a scalar, which is how we would do something within the Perl 5 language.

—John

  • Comment on Re^4: Internal representation of qr// compiled regular expressions

Replies are listed 'Best First'.
Re^5: Internal representation of qr// compiled regular expressions
by japhy (Canon) on May 24, 2006 at 11:46 UTC
    Yes. The stringification of a Regexp object goes through the magic system. The mg_obj member is how a Regexp object points to the internal representation of itself (the regexp struct).
    Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
    How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart
[reply]

      And what is: '(?^u:' ?

      When inspecting (using the EPIC/Eclipse Perl debugger) the internal composition of a compiled regex (for example:

      my $var = qr/abc/;

      then $var shows as:

       '(?^u:abc)'

      What is '(?^u:' ?

[reply]
[d/l]
[select]

        From Extended Patterns:

        (?^alupimsx)
        One or more embedded pattern-match modifiers, to be turned on (or turned off, if preceded by -) for the remainder of the pattern or the remainder of the enclosing pattern group (if any).

        and

        Starting in Perl 5.14, a "^" (caret or circumflex accent) immediately after the "?" is a shorthand equivalent to d-imsx.

        So, (?^u:abc) is shorthand for (?du-imsx:abc), which means (see Modifiers), match the string abc with:

        • /d    “the old, problematic, pre-5.14 Default character set behavior”;
        • /u    using the Unicode character set;
        • -i    with case-sensitive pattern matching;
        • -m    the string not treated as multiple lines ("^" and "$" match at the start or end, respectively, of the string);
        • -s    the "." pattern not matching the newline character; and
        • -x    whitespace and comments treated as patterns to be matched.

        Hope that helps,

        Athanasius <°(((>< contra mundum

[reply]

In Section Seekers of Perl Wisdom