package MemImpact;
use vars qw($before $after $now);
BEGIN {
    $before = `ps -o vsz= -p $$`;
}
$now = $before;
printf "%-40s % 10d kB\n", "initial memory:" , $before;
sub import {
    my $pack = shift;
    for (@_) {
        eval "use $_;";
        die "Can't load $_:\n$@\n" if $@;
        $after = `ps -o vsz= -p $$`;
        printf "%-40s % 10d kB\n", "after loading $_:" , $after;
        printf "%-40s % 10d kB\n", "impact of $_:" , $after - $now;
        $now = $after;
    }
}
END { printf "%-40s % 10d kB\n", "total impact:" , $after - $before; }
1;