Question

Specifically, is there a way to achieve the equivalent of

my $string = 'this is some example text';
my $match = qr/foobar/;
print 'success' if $string !~ $match;

By using only =~, and no negation operators?

Specifically, I need to ensure a string does NOT match a supplied value, and the testing function takes regex objects, and applies them positively to the value. The value must not occur in the searched string at all, complicating look-ahead and look-behind assertions.

Something like the following might be a good test:

my $string = 'this is some example text';
my $match =~ qr/foobar/;
# $negated_match contains $match, or some transformed variation of it
my $negated_match = qr/$YOUR_REGEX_HERE/; 
die 'failure' if $string =~ $match;
print 'success' if $string =~ $negated_match;

I suspect there’s a way to do this with look-around assertions, but haven’t puzzled it out yet. A perl specific answer is acceptable.

Answer 1

my $string = 'this is some example text';
my $match = qr/^(?!.*foobar)/s;
print 'success' if $string =~ $match;