gajus / paggern

Pattern interpreter for generating random strings.

Paggern

Pattern interpreter for generating random strings.

Generator

$generator = new \Gajus\Paggern\Generator();

/**
 * Generate a set of random codes based on Paggern pattern.
 * Codes are guaranteed to be unique within the set.
 *
 * @param string $pattern Paggern pattern.
 * @param int $amount Number of codes to generate.
 * @param int $safeguard Number of additional codes generated in case there are duplicates that need to be replaced.
 * @return array
 */
$codes = $generator->generateFromPattern('FOO[A-Z]{10}[0-9]{2}', 100);

The above example will generate an array containing 100 codes, each prefixed with "FOO", followed by 10 characters from "ABCDEFGHKMNOPRSTUVWXYZ23456789" haystack and 2 numbers from "0123456789" haystack.

Paggern utilises RandomLib to generate the pattern matching random character pool.

Lexer

Lexer exposes a method to tokenise the string. Lexer is independant of the Generator. You can choose to interpret Lexer tokens using your own implementation of the Generator.

$lexer = new \Gajus\Paggern\Lexer();

/**
 * Tokeniser explodes input into components describing the properties expressed in the pattern.
 *
 * @param string $pattern
 * @param boolean $expand Augment token definition with the haystack of possible values.
 * @return array
 */
$lexer->tokenise('[a-c]{3}[1-3]{3}', true);

[
    [
        'type' => 'range',
        'token' => 'a-c',
        'repetition' => 3,
        'haystack' => 'abc'
    ],
    [
        'type' => 'range',
        'token' => '1-3',
        'repetition' => 3,
        'haystack' => 123
    ]
]

Supported Tokens

Literal

Pattern can consist of literal characters, e.g. prefix of suffix of the code.

$lexer->tokenise('abc');

[
    [
        'type' => 'literal',
        'string' => 'abc'
    ]
]

The above pattern commands that the string is literally "abc".

Range

Range can be either numeric or ASCII.

$lexer->tokenise('[a-z]');

In the [a-z] example, string must be a character from "abcdefghijklmnopqrstuvwxyz" haystack.

[
    [
        'type' => 'range',
        'token' => 'a-z',
        'repetition' => 1
    ]
]

Range with Repetition

If the character must occur more than once, use repetition.

$lexer->tokenise('[a-c]{3}');

In the [a-z]{3} example, string must consist of 3 characters from the "abc" haystack.

[
    [
        'type' => 'range',
        'token' => 'a-c',
        'repetition' => 3
    ]
]

Character Classes

Predefined character classes can be used instead of ranges.

Character Class	Range
\U	"ABCDEFGHKMNOPRSTUVWXYZ23456789" (or A-Z0-9 excluding IJLQ01) describes characters that are unambiguously recognised regardless of the font or case-sensitivity. The designated use case is voucher codes.

Character Classes with Repetition

Similar to the Range with Repetition, Character Classes can be used with repetition, e.g.

$lexer->tokenise('\U{3}');

Limitations

• Pattern cannot include []{} characters.
• Pattern cannot include characters outside of the ASCII.

paggern's Issues

Mock out the generator

Test cases should use a fake generator. This will reduce complexity of the test cases and make them not bound to random events.