| 1: | <?php declare(strict_types = 1); |
| 2: | |
| 3: | namespace PHPStan\Type; |
| 4: | |
| 5: | class TypeTraverser |
| 6: | { |
| 7: | |
| 8: | /** @var callable(Type $type, callable(Type): Type $traverse): Type */ |
| 9: | private $cb; |
| 10: | |
| 11: | /** |
| 12: | * Map a Type recursively |
| 13: | * |
| 14: | * For every Type instance, the callback can return a new Type, and/or |
| 15: | * decide to traverse inner types or to ignore them. |
| 16: | * |
| 17: | * The following example converts constant strings to objects, while |
| 18: | * preserving unions and intersections: |
| 19: | * |
| 20: | * TypeTraverser::map($type, function (Type $type, callable $traverse): Type { |
| 21: | * if ($type instanceof UnionType || $type instanceof IntersectionType) { |
| 22: | * // Traverse inner types |
| 23: | * return $traverse($type); |
| 24: | * } |
| 25: | * if ($type instanceof ConstantStringType) { |
| 26: | * // Replaces the current type, and don't traverse |
| 27: | * return new ObjectType($type->getValue()); |
| 28: | * } |
| 29: | * // Replaces the current type, and don't traverse |
| 30: | * return new MixedType(); |
| 31: | * }); |
| 32: | * |
| 33: | * @api |
| 34: | * @param callable(Type $type, callable(Type): Type $traverse): Type $cb |
| 35: | */ |
| 36: | public static function map(Type $type, callable $cb): Type |
| 37: | { |
| 38: | $self = new self($cb); |
| 39: | |
| 40: | return $self->mapInternal($type); |
| 41: | } |
| 42: | |
| 43: | /** @param callable(Type $type, callable(Type): Type $traverse): Type $cb */ |
| 44: | private function __construct(callable $cb) |
| 45: | { |
| 46: | $this->cb = $cb; |
| 47: | } |
| 48: | |
| 49: | /** @internal */ |
| 50: | public function mapInternal(Type $type): Type |
| 51: | { |
| 52: | return ($this->cb)($type, [$this, 'traverseInternal']); |
| 53: | } |
| 54: | |
| 55: | /** @internal */ |
| 56: | public function traverseInternal(Type $type): Type |
| 57: | { |
| 58: | return $type->traverse([$this, 'mapInternal']); |
| 59: | } |
| 60: | |
| 61: | } |
| 62: |