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.State

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+beta

README.md

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+![Hoa](http://static.hoa-project.net/Image/Hoa_small.png)
+
+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 ![state](http://central.hoa-project.net/State/Regex)
+
+This library provides tools to analyze regular expressions and generate strings
+based on regular expressions ([Perl Compatible Regular
+Expressions](http://pcre.org)).
+
+## Installation
+
+With [Composer](http://getcomposer.org/), to include this library into your
+dependencies, you need to require
+[`hoa/regex`](https://packagist.org/packages/hoa/regex):
+
+```json
+{
+    "require": {
+        "hoa/regex": "~0.0"
+    }
+}
+```
+
+Please, read the website to [get more informations about how to
+install](http://hoa-project.net/Source.html).
+
+## 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](http://central.hoa-project.net/Resource/Library/Compiler) to lex, parse
+and produce an AST of the following regular expression: `ab(c|d){2,4}e?`. Thus:
+
+```php
+// 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](http://central.hoa-project.net/Resource/Library/Visitor).
+
+### 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:
+
+```php
+$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
+
+Different documentations can be found on the website:
+[http://hoa-project.net/](http://hoa-project.net/).
+
+## License
+
+Hoa is under the New BSD License (BSD-3-Clause). Please, see
+[`LICENSE`](http://hoa-project.net/LICENSE).