Thanks! This is what I was looking for!
>>>-----Original Message----- >>>From: Thomas Bätzler [mailto:[EMAIL PROTECTED] >>>Sent: Tuesday, April 11, 2006 3:09 PM >>>To: beginners@perl.org >>>Cc: [EMAIL PROTECTED] >>>Subject: RE: Static variables in Perl? >>> >>>Hi, >>> >>>Dhanashri Bhate <[EMAIL PROTECTED]> asked: >>>[...] >>>> I can do something like suffixing the filename with timestamp >>>> etc, but would like to know if there can be a static variable >>>> defined in this function which will be incremented each time >>>> a new file is created. >>> >>>You can model such behaviour in Perl by using closures: >>> >>>#!/usr/bin/perl >>> >>>use strict; >>>use warnings; >>> >>>sub make_counter { >>> >>> # these variables are visible as static variables >>> # to the anonymous subroutine below >>> my( $start, $step ) = @_; >>> >>> # returns a reference to a subroutine that can be >>> # called by using the $var->() notation. >>> return sub { >>> return $start += $step; >>> } >>>} >>> >>>my $add_one = make_counter(0,1); >>>my $sub_one = make_counter(5,-1); >>> >>>for( my $i = 0; $i < 5; $i++ ){ >>> print $add_one->() . " " . $sub_one->() . "\n"; >>>} >>>__END__ >>> >>>The above examples demonstrates their usage: You declare a >>>generator function that returns a code reference. Your "static" >>>variables are declared as lexicals in the scope of the generator >>>function, so that they are visible to an anonymous subroutine. >>> >>>A call to the generator function will create a fresh set of >>>lexical variables that will remain accessible to the code of >>>the code reference that is passed back to you. >>> >>>For the full scoop on closures and really good examples I'd >>>recommend the book "Higher-order Perl" by Mark Jason Dominus. >>> >>>HTH, >>>Thomas -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
