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 around mathemetical operations.
With Composer, to include this library into your dependencies, you need to require hoa/math:
{ "require": { "hoa/math": "~0.0" } }Please, read the website to get more informations about how to install.
We propose a quick overview of one feature: 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) */Different documentations can be found on the website: http://hoa-project.net/.
Hoa is under the New BSD License (BSD-3-Clause). Please, see LICENSE.