PHP Parser
This is a PHP 5.2 to PHP 8.1 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 8.1).
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:
<?php
use PhpParser\Error;
use PhpParser\NodeDumper;
use PhpParser\ParserFactory;
$code = <<<'CODE'
<?php
function test($foo)
{
var_dump($foo);
}
CODE;
$parser = (new ParserFactory)->create(ParserFactory::PREFER_PHP7);
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(
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:
use PhpParser\Node;
use PhpParser\Node\Stmt\Function_;
use PhpParser\NodeTraverser;
use PhpParser\NodeVisitorAbstract;
$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(
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:
use PhpParser\PrettyPrinter;
$prettyPrinter = new PrettyPrinter\Standard;
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
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
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