PHP Parser

This is a PHP 5.2 to PHP 8.0 parser written in PHP. Its purpose is to simplify static code analysis and manipulation.

Documentation for version 4.x (stable; for running on PHP >= 7.0; for parsing PHP 5.2 to PHP 8.0).

Documentation for version 3.x (unsupported; for running on PHP >= 5.5; for parsing PHP 5.2 to PHP 7.2).

Features

The main features provided by this library are:

• Parsing PHP 5, 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.
  • Experimental: 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:

<?phpusePhpParser\Error;
usePhpParser\NodeDumper;
usePhpParser\ParserFactory;
$code = <<<'CODE'<?phpfunction test($foo){ var_dump($foo);}
CODE;
$parser = (newParserFactory)->create(ParserFactory::PREFER_PHP7);
try {
$ast = $parser->parse($code);
} catch (Error$error) {
echo"Parse error: {$error->getMessage()}\n";
return;
}
$dumper = newNodeDumper;
echo$dumper->dump($ast) . "\n";

This dumps an AST looking something like this:

array(
0: Stmt_Function(
byRef: false
name: Identifier(
name: test
)
params: array(
0: Param(
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(
parts: array(
0: var_dump
)
)
args: array(
0: Arg(
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:

usePhpParser\Node;
usePhpParser\Node\Stmt\Function_;
usePhpParser\NodeTraverser;
usePhpParser\NodeVisitorAbstract;
$traverser = newNodeTraverser();
$traverser->addVisitor(newclassextends NodeVisitorAbstract {
publicfunctionenterNode(Node$node) {
if ($nodeinstanceof Function_) {
// Clean out the function body$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(
byRef: false
name: Identifier(
name: test
)
params: array(
0: Param(
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:

usePhpParser\PrettyPrinter;
$prettyPrinter = newPrettyPrinter\Standard;
echo$prettyPrinter->prettyPrintFile($ast);

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

<?phpfunctiontest($foo)
{
}

For a more comprehensive introduction, see the documentation.

Documentation

1. Introduction
2. 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
  • Lexer options
  • Token and file positions for nodes
  • Custom 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