while ( my $value = some_sub() ) {
    # do something
    my $other_value = some_sub();
}

##</code><code>##

sub some_sub {
    my @caller = caller();
    # now I know where I was called
}

##</code><code>##

for ( 1 .. 10 ) {
    my ( $foo, $bar ) = ( some_sub(), some_sub() );
    # do stuff
}