use strict;
use warnings;
use feature 'say';

# This tests whether a pattern matches a string.
my $match = "peach" =~ /p([a-z]+)ch/;
say $match ? "true" : "false";

# We'll use this pattern for the following examples
my $pattern = qr/p([a-z]+)ch/;

# This is equivalent to the MatchString method in Go
say $pattern =~ /peach/ ? "true" : "false";

# This finds the match for the regexp.
if ("peach punch" =~ $pattern) {
    say $&;
}

# This also finds the first match but returns the
# start and end indexes for the match instead of the
# matching text.
if ("peach punch" =~ $pattern) {
    say "idx: [$-[0], $+[0]]";
}

# The capturing parentheses in the pattern allow us to extract
# submatches. This is similar to FindStringSubmatch in Go.
if ("peach punch" =~ $pattern) {
    say "[$&, $1]";
}

# To get all matches (like FindAllString in Go), we use the /g flag
my @matches = "peach punch pinch" =~ /$pattern/g;
say "[" . join(", ", @matches) . "]";

# To limit the number of matches, we can use a loop
my @limited_matches;
while ("peach punch pinch" =~ /$pattern/g) {
    push @limited_matches, $&;
    last if @limited_matches == 2;
}
say "[" . join(", ", @limited_matches) . "]";

# Perl's regexes work on both strings and binary data by default

# When creating global variables with regular expressions,
# you can use the qr// operator to pre-compile the regex
my $r = qr/p([a-z]+)ch/;
say "regexp: $r";

# The s/// operator can be used to replace subsets of strings
my $replaced = "a peach";
$replaced =~ s/$r/<fruit>/;
say $replaced;

# We can also use a function to transform matched text
my $transformed = "a peach";
$transformed =~ s/$r/uc($&)/e;
say $transformed;