This is my first attempt in using a closure as an itterator.
I noticed that I had several scripts
with cut-n-pasted code for deciding which lines in
a datafile to process. I'm trying to consolidate
that logic by using an itterator/closure
instead. It seems to work just fine, but since I'm breaking new ground (for me, at least) I thought I'd ask for a little peer review.
Thanks.
package My::Package;
my $datafile = '/path/to/data.txt';
# each line in file has a numbered key ($key) followed by
# some data. file is sorted based on incrementing keys
sub itter_maker { # return a function that passes back
# data only from lines with keys between
# $min and $max
my $min = shift;
my $max = shift;
my $done;
my $fh = new IO::File "$datafile";
return(
sub {
return if $done;
my (@data,$row,$key);
while (1) {
chomp($row = <$fh>) or last;
####
# [SNIPPED] munge $row, set $key and @data
####
next if $key < $min;
$done = 1 && return if ($key > $max);
last;
}
return ($key,\@data);
});
}
And its used as such:
#!/usr/bin/perl
use My::Package;
# only loop through lines with "30 <= $key <= 70"
my $nextrow = itter_maker(30,70);
while (my ($num,$dataref) = $nextrow->()) {
### do stuff
}
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