PHP Parser

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

Note: This project is highly experimental. It may not always function correctly.

Components

This package currently bundles several components:

• The Parser itself
• A NodeDumper to dump the nodes to a human readable string representation
• A PrettyPrinter to translate the node tree back to PHP

Autoloader

In order to automatically include required files PHPParser_Autoloader can be used:

require_once 'path/to/phpparser/lib/PHPParser/Autoloader.php';
PHPParser_Autoloader::register();

Parser and ParserDebug

Parsing is performed using PHPParser_Parser->parse(). This method accepts a PHPParser_Lexer as the only parameter and returns an array of statement nodes. If an error occurs it throws a PHPParser_ParseErrorException.

$code = '<?php // some code';

try {
    $parser = new PHPParser_Parser;
    $stmts = $parser->parse(new PHPParser_Lexer($code));
} catch (PHPParser_ParseErrorException $e) {
    echo 'Parse Error: ', $e->getMessage();
}

The PHPParser_ParserDebug class also parses a PHP code, but outputs a debug trace while doing so.

Node Tree

The output of the parser is an array of statement nodes. All nodes are instances of PHPParser_NodeAbstract. Furthermore nodes are divided into three categories:

• PHPParser_Node_Stmt: A statement
• PHPParser_Node_Expr: An expression
• PHPParser_Node_Scalar: A scalar (which is a string, a number, aso.) PHPParser_Node_Scalar inherits from PHPParser_Node_Expr.

Each node may have subnodes. For example PHPParser_Node_Expr_Plus has two subnodes, namely left and right, which represend the left hand side and right hand side expressions of the plus operation. Subnodes are accessed as normal properties:

$node->left

The subnodes which a certain node can have are documented as @property doccomments in the respective files.

NodeDumper

Nodes can be dumped into a string representation using the PHPParser_NodeDumper->dump() method:

$code = <<<'CODE'
<?php
    function printLine($msg) {
        echo $msg, "\n";
    }

    printLine('Hallo World!!!');
CODE;

try {
    $parser = new PHPParser_Parser;
    $stmts = $parser->parse(new PHPParser_Lexer($code));

    $nodeDumper = new PHPParser_NodeDumper;
    echo '<pre>' . htmlspecialchars($nodeDumper->dump($stmts)) . '</pre>';
} catch (PHPParser_ParseErrorException $e) {
    echo 'Parse Error: ', $e->getMessage();
}

This script will have an output similar to the following:

array(
    0: Stmt_Func(
        byRef: false
        name: printLine
        params: array(
            0: Stmt_FuncParam(
                type: null
                name: msg
                byRef: false
                default: null
            )
        )
        stmts: array(
            0: Stmt_Echo(
                exprs: array(
                    0: Variable(
                        name: msg
                    )
                    1: Scalar_String(
                        value:

                        isBinary: false
                        type: 1
                    )
                )
            )
        )
    )
    1: Expr_FuncCall(
        func: Name(
            parts: array(
                0: printLine
            )
        )
        args: array(
            0: Expr_FuncCallArg(
                value: Scalar_String(
                    value: Hallo World!!!
                    isBinary: false
                    type: 0
                )
                byRef: false
            )
        )
    )
)

PrettyPrinter

The pretty printer compiles nodes back to PHP code. "Pretty printing" here is just the formal name of the process and does not mean that the output is in any way pretty.

$prettyPrinter = new PHPParser_PrettyPrinter_Zend;
echo '<pre>' . htmlspecialchars($prettyPrinter->prettyPrint($stmts)) . '</pre>';

For the code mentioned in the above section this should create the output:

function printLine($msg)
{
    echo $msg, "\n";
}
printLine('Hallo World!!!');