#!/usr/bin/perl 

use Test2::V0;

sub do_not_match {
	my $pat = shift;
	return qr{(?:.*?(?=$pat))|(?:(?:.(?!$pat))*)};
}

my $re = do_not_match(qr{\b[aeiou][a-z]*ion\b});

is [/($re)/], ['stimulated '], 'matches prefix'
    for 'stimulated emission of radiation';

is [/($re)/], ['electron transition'],'no match'
    for 'electron transition';

is [/($re)/], [''], 'matches empty prefix'
    for 'absorbtion of photons';

is [/($re)/], ['light '], 'matches not greedy'
    for 'light amplification by stimulated emission of radiation';

is [/($re)\bimpact/], ['electron '], 'gives characters back'
    for 'electron impact ionization';

done_testing;