NAME
Data::Random::String::Matches - Generate random strings matching a regex
SYNOPSIS
use Data::Random::String::Matches;
# Create generator with regex and optional length
my $gen = Data::Random::String::Matches->new(qr/[A-Z]{3}\d{4}/, 7);
# Generate a matching string
my $str = $gen->generate();
print $str; # e.g., "XYZ1234"
# Alternation
my $gen2 = Data::Random::String::Matches->new(qr/(cat|dog|bird)/);
my $animal = $gen2->generate_smart(); # "cat", "dog", or "bird"
# Backreferences
my $gen3 = Data::Random::String::Matches->new(qr/(\w{3})-\1/);
my $str3 = $gen3->generate_smart(); # e.g., "abc-abc"
# Groups and quantifiers
my $gen4 = Data::Random::String::Matches->new(qr/(ha){2,4}/);
my $laugh = $gen4->generate_smart(); # "haha", "hahaha", or "hahahaha"
DESCRIPTION
This module generates random strings that match a given regular expression pattern. It parses the regex pattern and intelligently builds matching strings, supporting a wide range of regex features.
SUPPORTED REGEX FEATURES
Character Classes
- Basic classes:
[a-z],[A-Z],[0-9],[abc] - Negated classes:
[^a-z] - Ranges:
[a-zA-Z0-9] - Escape sequences in classes:
[\d\w]
Escape Sequences
\d- digit [0-9]\w- word character [a-zA-Z0-9_]\s- whitespace\D- non-digit\W- non-word character\t,\n,\r- tab, newline, carriage return
Quantifiers
{n}- exactly n times{n,m}- between n and m times{n,}- n or more times+- one or more (1-5 times)*- zero or more (0-5 times)?- zero or one
Grouping and Alternation
(...)- capturing group(?:...)- non-capturing group|- alternation (e.g.,cat|dog|bird)\1,\2, etc. - backreferences
Other
.- any character (printable ASCII)- Literal characters
^and$anchors (stripped during parsing)
LIMITATIONS
- Lookaheads and lookbehinds are not supported
- Named groups are not supported
- Possessive quantifiers (
*+,++) are not supported - Unicode properties (
\p{}) are not supported - Some complex nested patterns may not work correctly
EXAMPLES
# Email-like pattern
my $gen = Data::Random::String::Matches->new(qr/[a-z]+@[a-z]+\.com/);
# API key pattern
my $gen = Data::Random::String::Matches->new(qr/^AIza[0-9A-Za-z_-]{35}$/);
# Phone number
my $gen = Data::Random::String::Matches->new(qr/\d{3}-\d{3}-\d{4}/);
# Repeated pattern
my $gen = Data::Random::String::Matches->new(qr/(\w{4})-\1/);
METHODS
new($regex, $length)
Creates a new generator. $regex can be a compiled regex (qr//) or a string.
$length is optional and defaults to 10 (used for fallback generation).
generate($max_attempts)
Generates a random string matching the regex. First tries smart parsing, then
falls back to brute force if needed. Tries up to $max_attempts times
(default 1000) before croaking.
generate_smart()
Parses the regex and builds a matching string directly. Faster and more reliable than brute force, but may not handle all edge cases.
create_random_string
For consistency with Data::Random::String.
print Data::Random::String->create_random_string(length => 3, regex => '\d{3}'), "\n";
AUTHOR
Nigel Horne, <njh at nigelhorne.com>
LICENSE
This is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
LICENCE AND COPYRIGHT
Copyright 2025 Nigel Horne.
Usage is subject to licence terms.
The licence terms of this software are as follows:
- Personal single user, single computer use: GPL2
- All other users (including Commercial, Charity, Educational, Government) must apply in writing for a licence for use from Nigel Horne at the above e-mail.