Perl 6 Deep Dive

:i (:ignorecase)

This is the simplest regex adverb. It allows the regex to be case-independent. Thus, each of the two regexes m:i/X/ and m:i/x/ will both successfully match with x and X:

my $rx = rx:i/hello/;say 'Matches' if 'Hello, World!' ~~ $rx; 

When the :i adverb is located inside the regex, then only the following part is case-insensitive:

say 'No match' if 'HeLLO, World!' !~~ /he :i llo/; say 'Matches'  if 'HeLLO, World!'  ~~ /He :i llo/;

To stop the action of the adverb, use the negated version:

say 'Matches' if 'HeLLo, World!' ~~ /He :i ll :!i o/; 

Capturing and non-capturing braces limit the scope of an adverb:

say 'Not OK' if $str !~~ / (:i hello)\, \s world /;say 'OK' if $str ~~ / [:i hello]\, \s World /;

In these examples, :i