README

Example

Simple equation parsing

use RR\Shunt\Parser; $equation = '3 + 4 * 2 / ( 1 - 5 ) ^ 2 ^ 3'; $result = Parser::parse($equation); echo $result; //3.0001220703125

Equation with constants and functions

use RR\Shunt\Parser; use RR\Shunt\Context; $ctx = new Context(); $ctx->def('abs'); // wrapper for PHP "abs" function $ctx->def('foo', 5); // constant "foo" with value "5" $ctx->def('bar', function($a, $b) { return $a * $b; }); // define function $equation = '3 + bar(4, 2) / (abs(-1) - foo) ^ 2 ^ 3'; $result = Parser::parse($equation, $ctx); echo $result; //3.0001220703125

Test a condition

use RR\Shunt\Parser; use RR\Shunt\Context; $ctx = new Context(); $ctx->def('foo', 5); // constant "foo" with value "5" $equation = '(foo > 3) & (foo < 6)'; $result = Parser::parse($equation, $ctx); echo $result; //true

Re-run parsed expression on multiple inputs

use RR\Shunt\Parser; use RR\Shunt\Context; $counter = 1; $ctx = new Context(); $ctx->def('data', function() { global $counter; return $counter++; }); // define function $ctx->def('bar', function($a) { return 2*$a; }); // define function $equation = 'bar(data())'; $parser = new Parser(new Scanner($equation)); $result = $parser->reduce($this->ctx); // first result echo $result; // 2 $result = $parser->reduce($this->ctx); // second result echo $result; // 4

Installation

Define the following requirement in your composer.json file:

{ "require": { "andig/php-shunting-yard": "dev-master" } }

Authors

Originally source code taken from https://github.com/droptable/php-shunting-yard, some changes from:

• https://github.com/andig/php-shunting-yard
• https://github.com/pmishev/php-shunting-yard
• https://github.com/falahati/php-shunting-yard

Test cases and refactoring for composer/packagist by https://github.com/sergej-kurakin/php-shunting-yard.