Re: explain code section please...

Thanks for the replies, it is very helpful. One more question, is the
subroutine called for as many elements that there are in the bin
directory, or is the subroutine being invoked only once and the
contents of bin are being copied into the subroutine to be worked on

Thanks



John W. Krahn wrote:
onlineviewer wrote:

Can someone please explain this code section to me. This is from the
O'reilly book. learning objects,references. I see the end result, but i
am not sure how and in what order it runs. I see that the $callback
variable is a reference to the subroutine,
'create_find_callback_that_sums_the_size'

Wrong. $callback is a reference to an anonymous sub that is CREATED by
'create_find_callback_that_sums_the_size'.

perldoc -q closure


then the find method is
called with the $callback reference and the bin directory.

Correct.


Then the
subroutine executes on each of the contents of the bin directory. Is
that right so far ?? Thanks...

File::Find::find traverses the directory tree starting at 'bin' and for each
entry it calls the subroutine supplied by you and puts the name of that entry
in the $_ variable.


use File::Find;

sub create_find_callback_that_sums_the_size {
my $total_size = 0;

return sub {
if (@_) {
return $total_size;
} else {
$total_size += -s if -f;
}
};

}

my $callback = create_find_callback_that_sums_the_size( );
find($callback, "bin");
my $total_size = $callback->("dummy");
print "total size of bin is $total_size\n";


John
--
use Perl;
program
fulfillment

.

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