Hoa is a modular, extensible and
structured set of PHP libraries.
Moreover, Hoa aims at being a bridge between industrial and research worlds.
This library provides tools to analyze regular expressions and generate strings based on regular expressions (Perl Compatible Regular Expressions).
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.
Before running the test suites, the development dependencies must be installed:
$ composer installThen, to run all the test suites:
$ vendor/bin/hoa test:runFor more information, please read the contributor guide.
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.
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.
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.
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 --openMore documentation can be found on the project's website: hoa-project.net.
There are mainly two ways to get help:
- On the
#hoaprojectIRC channel, - On the forum at users.hoa-project.net.
Do you want to contribute? Thanks! A detailed contributor guide explains everything you need to know.
Hoa is under the New BSD License (BSD-3-Clause). Please, see
LICENSE for details.
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