why are function calls in Perl loops so slow?

Question

I was writing a file parser in Perl, so had to loop through file. File consists of fixed length records and I wanted to make a separate function that parses given record and cal

Answer 1

The perl optimizer is constant-folding the sprintf calls in your sample code.

You can deparse it to see it happening:

$ perl -MO=Deparse sample.pl
foreach $_ (1 .. 10000000) {
    $a = &get_string();
}
sub get_string {
    return "abc\n";
}
foreach $_ (1 .. 10000000) {
    $a = "abc\n";
}
- syntax OK