PHP Parser

This is a PHP parser written in PHP. Its purpose is to simplify static code analysis and manipulation.

Documentation for version 5.x (current; for running on PHP >= 7.4; for parsing PHP 7.0 to PHP 8.3, with limited support for parsing PHP 5.x).

Documentation for version 4.x (supported; for running on PHP >= 7.0; for parsing PHP 5.2 to PHP 8.3).

Features

The main features provided by this library are:

Parsing PHP 7, and PHP 8 code into an abstract syntax tree (AST). Invalid code can be parsed into a partial AST. The AST contains accurate location information. Dumping the AST in human-readable form. Converting an AST back to PHP code. Formatting can be preserved for partially changed ASTs. Infrastructure to traverse and modify ASTs. Resolution of namespaced names. Evaluation of constant expressions. Builders to simplify AST construction for code generation. Converting an AST into JSON and back.

Quick Start

Install the library using composer:

php composer.phar require nikic/php-parser

Parse some PHP code into an AST and dump the result in human-readable form:

<?php use PhpParserError; use PhpParserNodeDumper; use PhpParserParserFactory; $code = <<<'CODE' <?php function test($foo) { var_dump($foo); } CODE; $parser = (new ParserFactory())->createForNewestSupportedVersion(); try { $ast = $parser->parse($code); } catch (Error $error) { echo "Parse error: {$error->getMessage()}n"; return; } $dumper = new NodeDumper; echo $dumper->dump($ast) . "n";

This dumps an AST looking something like this:

array( 0: Stmt_Function( attrGroups: array( ) byRef: false name: Identifier( name: test ) params: array( 0: Param( attrGroups: array( ) flags: 0 type: null byRef: false variadic: false var: Expr_Variable( name: foo ) default: null ) ) returnType: null stmts: array( 0: Stmt_Expression( expr: Expr_FuncCall( name: Name( name: var_dump ) args: array( 0: Arg( name: null value: Expr_Variable( name: foo ) byRef: false unpack: false ) ) ) ) ) ) )

Let's traverse the AST and perform some kind of modification. For example, drop all function bodies:

use PhpParserNode; use PhpParserNodeStmtFunction_; use PhpParserNodeTraverser; use PhpParserNodeVisitorAbstract; $traverser = new NodeTraverser(); $traverser->addVisitor(new class extends NodeVisitorAbstract { public function enterNode(Node $node) { if ($node instanceof Function_) { // Clean out the function body $node->stmts = []; } } }); $ast = $traverser->traverse($ast); echo $dumper->dump($ast) . "n";

This gives us an AST where the Function_::$stmts are empty:

array( 0: Stmt_Function( attrGroups: array( ) byRef: false name: Identifier( name: test ) params: array( 0: Param( attrGroups: array( ) type: null byRef: false variadic: false var: Expr_Variable( name: foo ) default: null ) ) returnType: null stmts: array( ) ) )

Finally, we can convert the new AST back to PHP code:

use PhpParserPrettyPrinter; $prettyPrinter = new PrettyPrinterStandard; echo $prettyPrinter->prettyPrintFile($ast);

This gives us our original code, minus the var_dump() call inside the function:

<?php function test($foo) { }

For a more comprehensive introduction, see the documentation.

Documentation

Introduction Usage of basic components

Component documentation:

Walking the AST Node visitors Modifying the AST from a visitor Short-circuiting traversals Interleaved visitors Simple node finding API Parent and sibling references Name resolution Name resolver options Name resolution context Pretty printing Converting AST back to PHP code Customizing formatting Formatting-preserving code transformations AST builders Fluent builders for AST nodes Lexer Emulation Tokens, positions and attributes Error handling Column information for errors Error recovery (parsing of syntactically incorrect code) Constant expression evaluation Evaluating constant/property/etc initializers Handling errors and unsupported expressions JSON representation JSON encoding and decoding of ASTs Performance Disabling Xdebug Reusing objects Garbage collection impact Frequently asked questions Parent and sibling references