PHP calculator which evaluates different arithmetic expressions:

2+5.9 = 7.9 3.5^(2-5) = 0.02332361516035 5-(2*(1+2)) = -1 

The included functions by default are sqrt(x) and log(base, arg), but there is also an option to add custom functions with any number of arguments.

use \Fintara\Tools\Calculator\Calculator; $calculator = Calculator::create(); // use default tokenizer echo $calculator->calculate('1+2*3/4'); // 2.5

You can add custom functions:

• name: name of the function, as it will be used in expressions. All lower case and _ (underscore) allowed.
• implementation: how to evaluate the function.

$calculator->addFunction('cbrt', function($x) { return pow($x, 1/3); }); echo $calculator->calculate('cbrt(27)'); // 3

You can also use the tokenizer (or supply calculator with your own):

$tokenizer = new Tokenizer(); $tokens = $tokenizer->tokenize('1+2*3.5'); // [1, '+', 2, '*', 3.5]

In case the expression contains functions (e.g. sqrt(x)), the tokenizer needs to know all functions' names as second parameter.

$tokens = $tokenizer->tokenize('1+sqrt(4)', ['sqrt']); // [1, '+', 'sqrt', '(', 4, ')']

Note: The default tokenizer automatically adds * (multiplication) sign between a number and following function or a number and following parenthesis (if the sign is not found).

$tokens = $tokenizer->tokenize('2 (1 + 3)'); // [2, '*', '(', 1, '+', 3, ')']

2.0.1

• Added LICENSE

2.0.0

• Breaking: operator mod is renamed to %.
• Breaking: addFunction does not need number of arguments anymore (removed 3rd argument).
• Breaking: adding function with existing name throws. You can use the helper replaceFunction.
• Breaking: getReversePolishNotation is private.
• Breaking: setExpression is removed. Use directly calculate($expression).
• Breaking: ILexer and DefaultLexer are replaced with TokenizerInterface and Tokenizer respectively.