README

A PHP library for parsing arithmetic expressions and functions in different programming languages

Installation

composer require anastasd/expression-parser

How can the Expression Parser help?

If you need to run code that uses unsafe input, the parser ensures no harm is done to the server or other code.
If the eval() function is unavailable on your server, the evaluator can replace it.
If you want to restrict the input functions to a specific list, a custom-built parser can handle that for you.
If you want to “translate” expressions written in other programming languages or even spreadsheet functions to PHP, the parser can do that.

Use cases

An online spreadsheet application that uses backend evaluation of cell content;
Any application that requires custom mathematical logic;
and many more ...

Limitations

Unary operators are not available (yet), just binary.

Examples

<?php
$settings = new Settings(Settings::PHP);
$parser = new Parser($settings);

$input = '-pow($a, 2) * sin(log($b)) + cos(sqrt($c)) * exp(tan($d)) / log(abs($e)) - sqrt(pow($f, 3))';

echo $parser->parse($input, ['$a', '$b', '$c', '$d', '$e', '$f'])
     ->prepare()
     ->compile();

The output is function expressionResult( $a,$b,$c,$d,$e,$f ){ $param_24=3;$param_2=$a;$param_3=2;$param_23=$f;$param_7=$b;$param_19=$e;$param_11=$c;$param_15=$d;$param_22=pow($param_23, $param_24);$param_21=$param_22;$param_20=sqrt($param_21);$param_18=abs($param_19);$param_17=$param_18;$param_16=log($param_17, M_E);$param_14=tan($param_15);$param_13=$param_14;$param_12=exp($param_13);$param_10=sqrt($param_11);$param_9=$param_10;$param_8=cos($param_9);$param_6=log($param_7, M_E);$param_5=$param_6;$param_4=sin($param_5);$param_1=pow($param_2, $param_3);$param_0_0=$param_1*$param_4;$param_0_1=$param_8*$param_12;$param_0_2=$param_0_1/$param_16;$param_0_3=0-$param_0_0;$param_0_4=$param_0_2-$param_20;$param_0_5=$param_0_3+$param_0_4; return $param_0_5 ;}

<?php
$settings = new Settings(Settings::PHP);
$parser = new Parser($settings);

$input = '-pow($a, 2) * sin(log($b)) + cos(sqrt($c)) * exp(tan($d)) / log(abs($e)) - sqrt(pow($f, 3))';

echo $parser->parse($input, ['$a', '$b', '$c', '$d', '$e', '$f'])
     ->prepare()
     ->evaluate([1, 2, 3, 4, 5, 6]);

The output is -15.653432949851

anastasd / expression-parser

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