xref: /PHP-Parser/UPGRADE-2.0.md (revision c542e5d8)
1Upgrading from PHP-Parser 1.x to 2.0
2====================================
3
4### PHP version requirements
5
6PHP-Parser now requires PHP 5.4 or newer to run. It is however still possible to *parse* PHP 5.2 and
7PHP 5.3 source code, while running on a newer version.
8
9### Creating a parser instance
10
11Parser instances should now be created through the `ParserFactory`. Old direct instantiation code
12will not work, because the parser class was renamed.
13
14Old:
15
16```php
17use PhpParser\Parser, PhpParser\Lexer;
18$parser = new Parser(new Lexer\Emulative);
19```
20
21New:
22
23```php
24use PhpParser\ParserFactory;
25$parser = (new ParserFactory)->create(ParserFactory::PREFER_PHP7);
26```
27
28The first argument to `ParserFactory` determines how different PHP versions are handled. The
29possible values are:
30
31 * `ParserFactory::PREFER_PHP7`: Try to parse code as PHP 7. If this fails, try to parse it as PHP 5.
32 * `ParserFactory::PREFER_PHP5`: Try to parse code as PHP 5. If this fails, try to parse it as PHP 7.
33 * `ParserFactory::ONLY_PHP7`: Parse code as PHP 7.
34 * `ParserFactory::ONLY_PHP5`: Parse code as PHP 5.
35
36For most practical purposes the difference between `PREFER_PHP7` and `PREFER_PHP5` is mainly whether
37a scalar type hint like `string` will be stored as `'string'` (PHP 7) or as `new Name('string')`
38(PHP 5).
39
40To use a custom lexer, pass it as the second argument to the `create()` method:
41
42```php
43use PhpParser\ParserFactory;
44$lexer = new MyLexer;
45$parser = (new ParserFactory)->create(ParserFactory::PREFER_PHP7, $lexer);
46```
47
48### Rename of the `PhpParser\Parser` class
49
50`PhpParser\Parser` is now an interface, which is implemented by `Parser\Php5`, `Parser\Php7` and
51`Parser\Multiple`. Parser tokens are now defined in `Parser\Tokens`. If you use the `ParserFactory`
52described above to create your parser instance, these changes should have no further impact on you.
53
54### Removal of legacy aliases
55
56All legacy aliases for classes have been removed. This includes the old non-namespaced `PHPParser_`
57classes, as well as the classes that had to be renamed for PHP 7 support.
58
59### Deprecations
60
61The `set()`, `setFirst()`, `append()` and `prepend()` methods of the `Node\Name` class have been
62deprecated. Instead `Name::concat()` and `Name->slice()` should be used.
63
64### Miscellaneous
65
66* The `NodeTraverser` no longer clones nodes by default. If you want to restore the old behavior,
67  pass `true` to the constructor.
68* The legacy node format has been removed. If you use custom nodes, they are now expected to
69  implement a `getSubNodeNames()` method.
70* The default value for `Scalar` node constructors was removed. This means that something like
71  `new LNumber()` should be replaced by `new LNumber(0)`.
72* String parts of encapsed strings are now represented using `Scalar\EncapsStringPart` nodes, while
73  previously raw strings were used. This affects the `parts` child of `Scalar\Encaps` and
74  `Expr\ShellExec`.