226 lines
5.9 KiB
Markdown
226 lines
5.9 KiB
Markdown
PHP Parser
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==========
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[![Coverage Status](https://coveralls.io/repos/github/nikic/PHP-Parser/badge.svg?branch=master)](https://coveralls.io/github/nikic/PHP-Parser?branch=master)
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This is a PHP 5.2 to PHP 8.2 parser written in PHP. Its purpose is to simplify static code analysis and
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manipulation.
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[**Documentation for version 4.x**][doc_4_x] (stable; for running on PHP >= 7.0; for parsing PHP 5.2 to PHP 8.2).
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[Documentation for version 3.x][doc_3_x] (unsupported; for running on PHP >= 5.5; for parsing PHP 5.2 to PHP 7.2).
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Features
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--------
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The main features provided by this library are:
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* Parsing PHP 5, PHP 7, and PHP 8 code into an abstract syntax tree (AST).
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* Invalid code can be parsed into a partial AST.
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* The AST contains accurate location information.
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* Dumping the AST in human-readable form.
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* Converting an AST back to PHP code.
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* Experimental: Formatting can be preserved for partially changed ASTs.
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* Infrastructure to traverse and modify ASTs.
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* Resolution of namespaced names.
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* Evaluation of constant expressions.
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* Builders to simplify AST construction for code generation.
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* Converting an AST into JSON and back.
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Quick Start
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-----------
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Install the library using [composer](https://getcomposer.org):
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php composer.phar require nikic/php-parser
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Parse some PHP code into an AST and dump the result in human-readable form:
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```php
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<?php
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use PhpParser\Error;
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use PhpParser\NodeDumper;
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use PhpParser\ParserFactory;
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$code = <<<'CODE'
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<?php
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function test($foo)
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{
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var_dump($foo);
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}
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CODE;
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$parser = (new ParserFactory)->create(ParserFactory::PREFER_PHP7);
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try {
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$ast = $parser->parse($code);
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} catch (Error $error) {
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echo "Parse error: {$error->getMessage()}\n";
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return;
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}
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$dumper = new NodeDumper;
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echo $dumper->dump($ast) . "\n";
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```
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This dumps an AST looking something like this:
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```
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array(
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0: Stmt_Function(
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byRef: false
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name: Identifier(
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name: test
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)
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params: array(
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0: Param(
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type: null
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byRef: false
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variadic: false
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var: Expr_Variable(
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name: foo
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)
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default: null
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)
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)
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returnType: null
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stmts: array(
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0: Stmt_Expression(
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expr: Expr_FuncCall(
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name: Name(
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parts: array(
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0: var_dump
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)
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)
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args: array(
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0: Arg(
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value: Expr_Variable(
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name: foo
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)
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byRef: false
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unpack: false
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)
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)
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)
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)
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)
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)
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)
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```
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Let's traverse the AST and perform some kind of modification. For example, drop all function bodies:
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```php
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use PhpParser\Node;
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use PhpParser\Node\Stmt\Function_;
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use PhpParser\NodeTraverser;
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use PhpParser\NodeVisitorAbstract;
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$traverser = new NodeTraverser();
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$traverser->addVisitor(new class extends NodeVisitorAbstract {
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public function enterNode(Node $node) {
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if ($node instanceof Function_) {
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// Clean out the function body
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$node->stmts = [];
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}
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}
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});
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$ast = $traverser->traverse($ast);
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echo $dumper->dump($ast) . "\n";
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```
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This gives us an AST where the `Function_::$stmts` are empty:
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```
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array(
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0: Stmt_Function(
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byRef: false
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name: Identifier(
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name: test
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)
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params: array(
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0: Param(
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type: null
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byRef: false
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variadic: false
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var: Expr_Variable(
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name: foo
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)
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default: null
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)
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)
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returnType: null
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stmts: array(
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)
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)
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)
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```
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Finally, we can convert the new AST back to PHP code:
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```php
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use PhpParser\PrettyPrinter;
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$prettyPrinter = new PrettyPrinter\Standard;
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echo $prettyPrinter->prettyPrintFile($ast);
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```
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This gives us our original code, minus the `var_dump()` call inside the function:
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```php
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<?php
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function test($foo)
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{
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}
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```
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For a more comprehensive introduction, see the documentation.
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Documentation
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-------------
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1. [Introduction](doc/0_Introduction.markdown)
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2. [Usage of basic components](doc/2_Usage_of_basic_components.markdown)
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Component documentation:
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* [Walking the AST](doc/component/Walking_the_AST.markdown)
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* Node visitors
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* Modifying the AST from a visitor
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* Short-circuiting traversals
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* Interleaved visitors
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* Simple node finding API
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* Parent and sibling references
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* [Name resolution](doc/component/Name_resolution.markdown)
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* Name resolver options
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* Name resolution context
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* [Pretty printing](doc/component/Pretty_printing.markdown)
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* Converting AST back to PHP code
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* Customizing formatting
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* Formatting-preserving code transformations
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* [AST builders](doc/component/AST_builders.markdown)
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* Fluent builders for AST nodes
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* [Lexer](doc/component/Lexer.markdown)
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* Lexer options
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* Token and file positions for nodes
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* Custom attributes
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* [Error handling](doc/component/Error_handling.markdown)
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* Column information for errors
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* Error recovery (parsing of syntactically incorrect code)
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* [Constant expression evaluation](doc/component/Constant_expression_evaluation.markdown)
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* Evaluating constant/property/etc initializers
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* Handling errors and unsupported expressions
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* [JSON representation](doc/component/JSON_representation.markdown)
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* JSON encoding and decoding of ASTs
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* [Performance](doc/component/Performance.markdown)
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* Disabling Xdebug
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* Reusing objects
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* Garbage collection impact
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* [Frequently asked questions](doc/component/FAQ.markdown)
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* Parent and sibling references
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[doc_3_x]: https://github.com/nikic/PHP-Parser/tree/3.x/doc
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[doc_4_x]: https://github.com/nikic/PHP-Parser/tree/4.x/doc
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