---

Hoa is a modular, extensible and structured set of PHP libraries.
Moreover, Hoa aims at being a bridge between industrial and research worlds.

Hoa\Math

This library provides tools around mathematical operations.

Learn more.

Installation

With Composer, to include this library into your dependencies, you need to require hoa/math:

$ composer require hoa/math '~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

We propose a quick overview of one feature: evaluation of arithmetical expressions.

Evaluation of arithmetical expressions

The hoa://Library/Math/Arithmetic.pp describes the form of an arithmetical expression. Therefore, we will use the classical workflow when manipulating a grammar, that involves the Hoa\Compiler library and the Hoa\Math\Visitor\Arithmetic class.

// 1. Load the compiler.
$compiler = Hoa\Compiler\Llk::load(
    new Hoa\File\Read('hoa://Library/Math/Arithmetic.pp')
);

// 2. Load the visitor, aka the “evaluator”.
$visitor    = new Hoa\Math\Visitor\Arithmetic();

// 3. Declare the expression.
$expression = '1 / 2 / 3 + 4 * (5 * 2 - 6) * PI / avg(7, 8, 9)';

// 4. Parse the expression.
$ast        = $compiler->parse($expression);

// 5. Evaluate.
var_dump(
    $visitor->visit($ast)
);

/**
 * Will output:
 *     float(6.4498519738463)
 */

// Bonus. Print the AST of the expression.
$dump = new Hoa\Compiler\Visitor\Dump();
echo $dump->visit($ast);

/**
 * Will output:
 *     >  #addition
 *     >  >  #division
 *     >  >  >  token(number, 1)
 *     >  >  >  #division
 *     >  >  >  >  token(number, 2)
 *     >  >  >  >  token(number, 3)
 *     >  >  #multiplication
 *     >  >  >  token(number, 4)
 *     >  >  >  #multiplication
 *     >  >  >  >  #group
 *     >  >  >  >  >  #substraction
 *     >  >  >  >  >  >  #multiplication
 *     >  >  >  >  >  >  >  token(number, 5)
 *     >  >  >  >  >  >  >  token(number, 2)
 *     >  >  >  >  >  >  token(number, 6)
 *     >  >  >  >  #division
 *     >  >  >  >  >  token(constant, PI)
 *     >  >  >  >  >  #function
 *     >  >  >  >  >  >  token(id, avg)
 *     >  >  >  >  >  >  token(number, 7)
 *     >  >  >  >  >  >  token(number, 8)
 *     >  >  >  >  >  >  token(number, 9)
 */

We can add functions and constants on the visitor, thanks to the addFunction and addConstant methods. Thus, we will add the rand function (with 2 parameters) and the ANSWER constant, set to 42:

$visitor->addFunction('rand', function ($min, $max) {
    return mt_rand($min, $max);
});
$visitor->addConstant('ANSWER', 42);

$expression = 'rand(ANSWER / 2, ANSWER * 2)'
var_dump(
    $visitor->visit($compiler->parse($expression))
);

/**
 * Could output:
 *     int(53)
 */

Documentation

The hack book of Hoa\Math 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.

Related projects

The following projects are using this library:

• PSIH & PMSIpilot, PSIH is the leading French integrator of business intelligence solutions for the healthcare sector,
• PHP Telegram Bot, Telegram bot based on the official Telegram Bot API.