in reply to Win32 File Creation Weirdness, ActivePerl 5.8.8

Your expression:

my ($id) = /(\d+)$/ || /^(\d+)/;

will not work correctly because the first regular expression is evaluated in scalar context and so will return 1 when it matches and not the id number.

This will do what you want:

my $id = ( /(\d+)$/ )[ 0 ] || ( /^(\d+)/ )[ 0 ];

Or this:

my $id = /(\d+)$/ ? $1 : /^(\d+)/ ? $1 : ();

Replies are listed 'Best First'.
Re^2: Win32 File Creation Weirdness, ActivePerl 5.8.8
by missingthepoint (Friar) on Jul 07, 2009 at 09:59 UTC

    jwkrahn, I fixed the bug like so after taking a break - I'm rather sleep deprived :|

    my ($id) = /(\d+)$/;
unless (defined $id) { ($id) = /^(\d+)/ }

    [download]

    Windows never ceases to astonish me. Thanks all for your help :)

    The zeroeth step in writing a module is to make sure that there isn't already a decent one in CPAN. (-- Pod::Simple::Subclassing)
[reply]
[d/l]
      Windows never ceases to astonish me.
      You think that's astonishing? Brace yourself.

      The Windows CLI wants redirection operator characters (e.g.,  > < |) in a double-quoted string to be escaped with a  ^ (hat) character if they are preceded by an odd number of backslash-escaped double-quote characters in the string! (Don't even ask what happens if the backslash escapes are themselves backslash-escaped.)

      Consider (this just illustrates redirection-character escaping; the scalar/list context problem with the regex is not addressed): 

      C:\@Work\Perl\junque>dir
 Volume in drive C has no label.
 Volume Serial Number is EC11-ED1D

 Directory of C:\@Work\Perl\junque

07/07/2009  11:42 AM    <DIR>          .
07/07/2009  11:42 AM    <DIR>          ..
07/07/2009  11:41 AM    <DIR>          16
07/07/2009  11:41 AM    <DIR>          17 foo bar
07/07/2009  11:42 AM    <DIR>          18- baz quux
               0 File(s)              0 bytes
               5 Dir(s)  10,227,699,712 bytes free

C:\@Work\Perl\junque>perl -e
"for (<*>) {
   my ($id) = /(\d+)$/ || /^(\d+)/;
   print qq{$_ => \"id=^>$id\" => x \n};
   }
"
16 => "id=>1" => x
17 foo bar => "id=>17" => x
18- baz quux => "id=>18" => x

C:\@Work\Perl\junque>perl -e
"for (<*>) {
   my ($id) = /(\d+)$/ || /^(\d+)/;
   print qq{$_ => \"id=>$id\" => x \n};
   }
"
The system cannot find the path specified.

C:\@Work\Perl\junque>perl -e
"print qq{ (\") \n};
 for (^<*^>) {
   my ($id) = /(\d+)$/ ^|^| /^^(\d+)/;
   print qq{$_ =^> \"id=>$id\" =^> x \n};
   }
"
 (")
16 => "id=>1" => x
17 foo bar => "id=>17" => x
18- baz quux => "id=>18" => x
x => "id=>" => x

      [download]
      Enjoy!
[reply]
[d/l]
[select]

        I am speechless. Needing those chars escaped if preceded by an odd number of \"?? That requirement's straight out of Monty Python!

        The zeroeth step in writing a module is to make sure that there isn't already a decent one in CPAN. (-- Pod::Simple::Subclassing)
[reply]
[d/l]

In Section Seekers of Perl Wisdom