hoa / regex
The Hoa\Regex library.
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Requires
- hoa/consistency: ~1.0
- hoa/exception: ~1.0
- hoa/math: ~1.0
- hoa/protocol: ~1.0
- hoa/ustring: ~4.0
- hoa/visitor: ~2.0
This package is auto-updated.
Last update: 2021-09-20 08:31:44 UTC
README
Hoa is a modular, extensible and
structured set of PHP libraries.
Moreover, Hoa aims at being a bridge between industrial and research worlds.
Hoa\Regex
This library provides tools to analyze regular expressions and generate strings based on regular expressions (Perl Compatible Regular Expressions).
Installation
With Composer, to include this library into
your dependencies, you need to
require hoa/regex
:
$ composer require hoa/regex '~1.0'
For more installation procedures, please read the Source page.
Testing
Before running the test suites, the development dependencies must be installed:
$ composer install
Then, to run all the test suites:
$ vendor/bin/hoa test:run
For more information, please read the contributor guide.
Quick usage
As a quick overview, we propose to see two examples. First, analyze a regular expression, i.e. lex, parse and produce an AST. Second, generate strings based on a regular expression by visiting its AST with an isotropic random approach.
Analyze regular expressions
We need the Hoa\Compiler
library to lex, parse
and produce an AST of the following regular expression: ab(c|d){2,4}e?
. Thus:
// 1. Read the grammar. $grammar = new Hoa\File\Read('hoa://Library/Regex/Grammar.pp'); // 2. Load the compiler. $compiler = Hoa\Compiler\Llk\Llk::load($grammar); // 3. Lex, parse and produce the AST. $ast = $compiler->parse('ab(c|d){2,4}e?'); // 4. Dump the result. $dump = new Hoa\Compiler\Visitor\Dump(); echo $dump->visit($ast); /** * Will output: * > #expression * > > #concatenation * > > > token(literal, a) * > > > token(literal, b) * > > > #quantification * > > > > #alternation * > > > > > token(literal, c) * > > > > > token(literal, d) * > > > > token(n_to_m, {2,4}) * > > > #quantification * > > > > token(literal, e) * > > > > token(zero_or_one, ?) */
We read that the whole expression is composed of a single concatenation of two
tokens: a
and b
, followed by a quantification, followed by another
quantification. The first quantification is an alternation of (a choice betwen)
two tokens: c
and d
, between 2 to 4 times. The second quantification is the
e
token that can appear zero or one time.
We can visit the tree with the help of the Hoa\Visitor
library.
Generate strings based on regular expressions
To generate strings based on the AST of a regular expressions, we will use the
Hoa\Regex\Visitor\Isotropic
visitor:
$generator = new Hoa\Regex\Visitor\Isotropic(new Hoa\Math\Sampler\Random()); echo $generator->visit($ast); /** * Could output: * abdcde */
Strings are generated at random and match the given regular expression.
Documentation
The
hack book of Hoa\Regex
contains detailed information about how to use this library and how it works.
To generate the documentation locally, execute the following commands:
$ composer require --dev hoa/devtools $ vendor/bin/hoa devtools:documentation --open
More documentation can be found on the project's website: hoa-project.net.
Getting help
There are mainly two ways to get help:
- On the
#hoaproject
IRC channel, - On the forum at users.hoa-project.net.
Contribution
Do you want to contribute? Thanks! A detailed contributor guide explains everything you need to know.
License
Hoa is under the New BSD License (BSD-3-Clause). Please, see
LICENSE
for details.