Re: Flip-flop reset?

my @arr = ...;
sub mySub {
  goto &{ sub {  # added line
    foreach ( @arr ) {
      if ( /^PIDTAB/ ... /^\n/ ) {
        next if ( /^(PIDTAB|\n)/ );

        while ( /\s+(\d+):\s+(\d+)\s*:\S+:\S+:D\s+/g ) {
           # do something
        }
      }
    }
  }}  # added line
}
[download]

will do the trick, since the sub {} will get a new pad (where the .. state is stored) each time mySub is called. This only works if the sub is a closure (uses an outer lexical); otherwise, the sub{} is treated more as if it were a kind of constant, and doesn't get a new pad each time the reference is returned by sub. If @arr isn't lexical, you can still force a closure by replacing

goto &{ sub {
[download]

with

my $dummy; goto &{ sub { $dummy if 0;
[download]

Comment on Re: Flip-flop reset? Select or Download Code

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Re^2: Flip-flop reset? by runrig (Abbot) on May 31, 2007 at 23:12 UTC
I was recently wondering how to do this, and why a regular anonymous sub (w/o closures) wouldn't work. Then I found this node. Though my solution (before finding this) was to generate an anonymous sub using eval $string. E.g. `my $range_checker = eval 'sub { local $_ = shift; /foo/../bar/ }';` [download] At first, your way seems a little too indirect and magical, but it makes perfect sense if you create a 'flip-flop generator': `sub mk_flip_flop { my ( $re1, $re2 ) = @_; sub { local $_ = shift; /$re1/../$re2/ } }` [download]	[reply] [d/l] [select]
Re^2: Flip-flop reset? by ysth (Canon) on Aug 31, 2006 at 21:07 UTC
I was thinking, `local $.;` has the odd, but documented, effect of localizing the last-read-filehandle. Maybe it could be extended to localize the state of ../... too. :)	[reply] [d/l]