README

Validates callback signatures against a prototype.

Status

👁 Build Status
👁 Scrutinizer Code Quality
👁 Code Coverage

Usage

// Create a prototype function (can be any callable)
$prototype = function (A $a, B $b, $c): ?string {};

// Validate that callables match the prototype
$tests = [
 $prototype, // true
 function (A $a, B $b, $c) {}, // false - return type does not match
 function ($a, $b, $c): ?string {}, // true - arguments are contravariant
 function (A $a, B $b): ?string {}, // true - extra args don't cause errors
 function (A $a, B $b, $c, $d): ?string {}, // false - Insufficient args cause an error
 function (C $a, B $b, $c): ?string {}, // true if C is a supertype of A, false otherwise
 function (SuperTypeOfA $a, B $b, $c): ?string {}, // true
 function (A $a, B $b, $c): string {}, // true - return types are covariant
];

// Create a type from a prototype
$type = CallbackType::createFromCallable($prototype);

run_tests($type, $tests);

// ...or create a type by hand for more granular control over variance rules
$type = new CallbackType(
 new ReturnType(BuiltInTypes::STRING, ReturnType::NULLABLE | ReturnType::COVARIANT),
 new ParameterType('a', A::class),
 new ParameterType('b', B::class),
 new ParameterType('c')
);

run_tests($type, $tests);

function run_tests(CallbackType $type, array $tests)
{
 foreach ($tests as $test) {
 if ($type->isSatisfiedBy($test)) {
 echo "pass\n";
 } else {
 // CallbackType implements __toString() for easy inspections
 echo CallbackType::createFromCallable($test) . " does not satisfy {$type}\n";
 }
 }
}

TODO

• Lots more tests
• Explain (text explanation of why callback does not validate)