Re: Initialize variable in BEGIN

[ikegami]

Using -n just complicates things for nothing.

With -n:

#!/usr/bin/perl -n

use strict;
use warnings;

our $total;

BEGIN {
   $total = 0;
}

$total += $_;

END {
   print $total, "\n";
}

Without -n:

#!/usr/bin/perl

use strict;
use warnings;

my $total = 0;

while ( <> ) {
   $total += $_;
}

print $total, "\n";

One is clearly a million times better.

[pfaut]

It might make more sense if expressed as a one-liner.

$ for i in {1..10}; do echo $i; done | perl -ne 'BEGIN {our $prod = 1;
+} $prod *= $_; END { print $prod,$/; }'
3628800

[ikegami]

I wasn't saying that BEGIN is never useful. I was talking about in the situation at hand.

But even in your entirely different scenario, does it really make sense?

perl -nle'BEGIN { $prod = 1; } $prod *= $_; END { print $prod; }'

vs

perl -le'$prod = 1; $prod *= $_ while <>; print $prod;'