sufir/php-calc

Simple calculation expressions

sufir/php-calc

, _(*1)

Install

Via Composer, _(*2)

``` bash $ composer require sufir/php-calc, <sub>(*3)</sub>

## Usage

``` php
$lexer = new Lexer();
$converter = new Converter();
$calc = new Calc(20);

D&D d20 check example:

``` php $calc->registerFunction('d20', function () { return rand(1, 20); });, <sub>(*4)</sub>

$charAbilities = ['ability' => 15, /*... etc */]; $difficultyClass = 12; $checkExpr = 'd20() + ($ability / 2 – 5)';, <sub>(*5)</sub>

$tokens = $lexer->parse($checkExpr); $result = $calc->evaluate( $converter->converToPostfix($tokens), $charAbilities );, <sub>(*6)</sub>

// simple d20 ability check if ($result < $difficultyClass) { echo 'You fail!!!'; } else { echo 'Congratulation!'; }, <sub>(*7)</sub>

### Area of a circle example:
``` php
$expr = '$Pi*$r^2';
$radiusList = [5, 10, 15, 25, 50];
$calc->defineVar('$Pi', '3.14159265358979323846');
$tokens = $lexer->parse($expr);

foreach ($radiusList as $radius) {
    echo 'Pi * ', $radius , '^2 = ',
    $calc->evaluate(
        $converter->converToPostfix($tokens),
        ['r' => $radius]
    ),
    "\n";
}

/*
Pi * 5^2  = 78.53981633974483096150
Pi * 10^2 = 314.15926535897932384600
Pi * 15^2 = 706.85834705770347865350
Pi * 25^2 = 1963.49540849362077403750
Pi * 50^2 = 7853.98163397448309615000
*/

Normal (Gaussian) distribution example:

``` php $expr = 'normal_distribution(1, $s, $m)';, <sub>(*8)</sub>

$calc->defineVar('$s', 1); $calc->defineVar('$m', 0); $calc->registerFunction('normal_distribution', function ($x, $σ = 1, $μ = 0) { $Pi = '3.1415926536'; $p = bcmul( bcdiv( 1, bcmul($σ, pow(bcmul(2, $Pi), 0.5)) ), exp( -bcdiv( pow(bcsub($x, $μ), 2), bcmul(2, pow($σ, 2)) ) ) );, <sub>(*9)</sub>

return $p;

});, <sub>(*10)</sub>

$tokens = $lexer->parse($expr); $nd = $calc->evaluate($tokens);, <sub>(*11)</sub>

## Testing

``` bash
$ composer test

Credits

• Sufir

License

The MIT License (MIT)., <sub>(*12)</sub>