README

Simple expression parser.

Compatible with PHP 5.4 and up.

Basic usage

$parser = new Parser(new TokenTypesFactory(), new Lexer());
$evaluator = new Evaluator();
$expression = $parser->parse("2 + 2");
echo $evaluator->execute($expression);

Features

• binary operations + - * / % ^
• unary operations - sqrt ! sin cos tan
• brackets
• float variables
• constants pi, e

You can override TokenTypesFactory to add custom operations, variables or brackets. There are some classes of token types:

• BinaryOperation
• UnaryOperation
• Variable
• Brackets

For example, new operation 'func' may be added in method getUnaryOperations like this:

$operations[] = new UnaryOperation('func', function ($args) {
    return $args[0] / 2;
}, 15, UnaryOperation::PREFIX_NOTATION);