Extracting multiple lines of record/data using a subroutine or functions - perl

Question

Can you show me how to create a subroutine or function using this code?
Basically I want to make my code into a subroutine so I'll be able to re-use it without making my script too long.
Here is my script:
#!/usr/local/bin/perl
use strict;
use warnings;
use Data::Dumper;
use Carp qw(croak);
my #fields;
my ($tmp_var, $rec_type, $country, $header, $Combline, $records, $line);
my $filename = 'data5.txt';
open (my $input_fh, '<', $filename ) or croak "Can't open $filename: $!";
open my $OUTPUTA, ">", 'drp1.txt' or die $!;
open my $OUTPUTB, ">", 'drp2.txt' or die $!;
while (<$input_fh>) {
$line = _trim($_);
#fields = split (/\|/, $line);
$rec_type = $fields[0];
$country = $fields[1];
my $string = substr $fields[1], 0, 1;
$header = $line if(/^INVHDR/);
if ($rec_type eq 'INVDET') {
if ($string eq 'I') {
$records = $header . $line;
print $OUTPUTA $records, scalar <$input_fh>;
}
else {
$records = $header . $line;
print $OUTPUTB $records, scalar <$input_fh>;
}
}
}
close $OUTPUTA or die $!;
close $OUTPUTB or die $!;
sub _trim {
my $word = shift;
if ( $word ) {
$word =~ s/\s*\|/\|/g; #remove trailing spaces
$word =~ s/"//g; #remove double quotes
}
return $word;
}
This is the part of the script that I wanted to put in a subroutine or function:
$line = _trim($_);
#fields = split (/\|/, $line);
$rec_type = $fields[0];
$country = $fields[1];
my $string = substr $fields[1], 0, 1;
$header = $line if (/^INVHDR/);
if ($rec_type eq 'INVDET') {
if ($string eq 'I') {
$records = $header . $line;
print $OUTPUTA $records, scalar <$input_fh>;
}
else {
$records = $header . $line;
print $OUTPUTB $records, scalar <$input_fh>;
}
}

Answer 1

I would suggest breaking it out a little differently and expand on your _trim function, turning it into a parse function:
use strict;
use warnings;
open( my $input_fh, '<', 'data5.txt' ) or die "Can't open $filename: $!";
open( my $OUTPUTA, '>', 'drp1.txt' ) or die $!;
open( my $OUTPUTB, '>', 'drp2.txt' ) or die $!;
my $header = '';
while (<$input_fh>) {
if ($_ =~ /^INVHDR/) {
$header = $_;
}
if ($_ =~ /^INVDET/) {
my #data = parse($_);
my $line = $header . join('|', #data);
# scalar <$input_fh> is almost certainly not doing what you expect,
# though I'm not sure what you're try to accomplish with it
if ( $data[1] =~ /^I/ ) {
print $OUTPUTA $line;
} else {
print $OUTPUTB $line;
}
}
}
sub parse {
my $input = shift || return;
my $input =~ s/"//g; # remove double quotes
# Here I've combined the removal of trailing spaces with the split.
my #fields = split( m{\s*\|}, $input );
return #fields;
}