README

A formula-calculating library for php.

Installation

You can install this package with composer:

composer require puritandesigns/poindexter

Usage

Here are a few usage examples:

use Poindexter\Parsing\Parser;

// Simple arithmetic
Parser::calculate('1 + 1')->getValue(); // returns 2
Parser::calculate('2 * 2')->getValue(); // returns 4

// Comparisons
// returns 1 (truthy)
Parser::calculate('1 < 2')->getValue();
Parser::calculate('2 = 2')->getValue();
// returns 0 (falsy)
Parser::calculate('2 <= 1')->getValue();
Parser::calculate('1 = 2')->getValue();

// Logical Operators (returns binary value)
// and
Parser::calculate('1 & 1')->getValue(); // returns 1
Parser::calculate('1 & 0')->getValue(); // returns 0
Parser::calculate('0 & 0')->getValue(); // returns 0
// or
Parser::calculate('1 | 1')->getValue(); // returns 1
Parser::calculate('1 | 0')->getValue(); // returns 1
Parser::calculate('0 | 0')->getValue(); // returns 0

// Variables
Parser::calculate('x + y', ['x' => 1, 'y' => 2])->getValue();
Parser::calculate('long_name + y', ['long_name' => 1, 'y' => 2])->getValue();

// Simple parentheses
Parser::calculate('(1 + x) * (1 + y)', ['x' => 1, 'y' => 2])->getValue();

Caveats

A couple of things to keep in mind....

The Parser is pretty lazy.

It cannot parse nested parentheses in strings. It can with array inputs.

The Parser needs strings with space between elements: - 'x+y' would be understood as one variable instead of 3 distinct statements - 'x + y' would parse into the 3 statements: variable x, add, and variable y

You can manually build more-complicated statements from Factors objects

use Poindexter\Interfaces\ResultInterface;
use Poindexter\Factors;

$factors = [
    new Factors\Number(5),
    new Factors\Add(),
    new Factors\Parenthesis([
        new Factors\Number(5),
        new Factors\Add(),
        new Factors\Parenthesis([
            new Factors\Number(5),
            new Factors\Add(),
            new Factors\Number(5)
        ])
    ]),
    new Factors\Divide(),
    new Factors\Number(5)
];

$calculator = new \Poindexter\Calculator($factors, ResultInterface::INTEGER);

$calculator->calculate()->getValue();

See tests for more examples.

Be careful with Comparators

Incorporating <, >, =, &, etc... yields a binary (1 or 0) result for that particular expression. If you are not careful, that might change the intention of your formulas.