Overview

naotake51/evaluation is a Composer package for creating a simple expression evaluation module. It allows you to register your own functions to evaluate expressions (strings).

Using

use Naotake51\Evaluation\Evaluation;

$evaluation = new Evaluation([
    'square' => function (array $arguments) {
        return $arguments[0] * $arguments[0];
    }
]);
$result = $evaluation('square(2) + square(2)'); // => 8

Literal

type	example
int	123
float	0.5 .5
boolean	True true TRUE False false FALSE
string	"aaa" 'aaa' 'aa\'aa\\aa'
array	[1, 2, [3, 4]]
object	{'a': 1, 'b': {'c': 2}}

Operators and precedence

Operator	example
!	!true
* / %	5 * 2
+ -	5 + 2
== != === !==	1 === 1
&&	true && false
||	true || false

Magic function

identifier	description
__add	Override the binary operator '+'.
__sub	Override the binary operator '-'.
__mul	Override the binary operator '*'.
__div	Override the binary operator '/'.
__mod	Override the binary operator '%'.
__or	Override the binary operator '||'.
__and	Override the binary operator '&&'.
__equal	Override the binary operator '=='.
__not_equal	Override the binary operator '!='.
__equal_strict	Override the binary operator '==='.
__not_equal_strict	Override the binary operator '!=='.
__not	Override the unary operator '!'.

$evaluation = new Evaluation([
    '__add' => function (array $arguments) {
        return "$arguments[0] + $arguments[1]";
    }
]);
$result = $evaluation('1 + 2'); // => '1 + 2'

$evaluation = new Evaluation([
    '*' => function (string $identify, array $arguments) {
        return 'call' . $identify . '(' . implode(', ', $arguments). ')';
    }
]);
$result = $evaluation('hoge(1, 2)'); // => 'call hoge(1, 2)'

Parameter check

By passing an array, you can define the type of the argument. It is also possible to express OR by separating with '|'.

definition	description
numeric	Check with 'is_numeric'.
integer	Check with 'is_integer'.
float	Check with 'is_float'.
string	Check with 'is_string'.
bool	Check with 'is_bool'.
array	Check with 'is_array'.
object	Check with 'is_object'.
null	Check with 'is_null'.
mixed	All types are allowed.

$evaluation = new Evaluation([
    'repeat' => [
        'string, integer|null' => function (string $str, ?int $repeat) {
            return str_repeat($str, $repeat ?? 2);
        },
    ]
]);
$result = $evaluation("repeat('abc', 3)"); // => 'abcabcabc'

Overload

Multiple patterns can be overloaded by registering them.

$evaluation = new Evaluation([
    '__add' => [
        'string, string' => function (string $a, string $b) {
            return $a . $b;
        },
        'numeric, numeric' => function ($a, $b) {
            return $a + $b;
        },
    ]
]);
$result = $evaluation("'abc' + 'def'"); // => 'abcdef'

Run-time error

class	description
Errors\EvaluationError	Base class for errors that occur during evaluation.
Errors\SyntaxError	syntactic error.
Errors\UndefineFunctionError	Calling an undefined function.
Errors\ArgumentError	Error in parameter check.

use Naotake51\Evaluation\Evaluation;
use Naotake51\Evaluation\Errors\EvaluationError;

try {
    $evaluation = new Evaluation([
        'hoge' => function (array $arguments) {
            return 'hoge';
        },
    ]);
    $result = $evaluation("fuga()"); // => UndefineFunctionError
} catch (EvaluationError $e) {
    error_log($e->getMessage()); // => 'function fuga is not exists.'
}