What is the difference between Perl's ( or, and ) and ( ||, && ) short-circuit operators?

Question

Which of these subroutines is not like the other?

sub or1 {
    my ($a,$b) = @_;
    return $a || $b;
}

sub or2 {
    my ($a,$b) = @_;
    $a || $b;
}

sub          


        

Answer 1

What rules of thumb do you use to decide which construct to use and make sure the code is doing what you think it is doing

The operator precedence rules.

|| binds tightly, or binds weakly. There is no "rule of thumb".

If you must have a rule of thumb, how about "only use or when there is no lvalue":

or:

open my $fh, '>', 'file' or die "Failed to open file: $!"

||:

my $greeting = greet() || $fallback || 'OH HAI';

I agree with MJD about avoiding parens; if you don't know the rules, look them up... but don't write (open(my $fh, '>', 'file')) or (die("Failed to open file: $!")) "just to be sure", please.