php-parser/doc/3_Other_node_tree_representations.markdown

Other node tree representations
===============================

It is possible to convert the AST in several textual representations, which serve different uses.

Simple serialization
--------------------

It is possible to serialize the node tree using `serialize()` and also unserialize it using
`unserialize()`. The output is not human readable and not easily processable from anything
but PHP, but it is compact and generates fast. The main application thus is in caching.

Human readable dumping
----------------------

Furthermore it is possible to dump nodes into a human readable form using the `dump` method of
`PHPParser_NodeDumper`. This can be used for debugging.

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

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

$parser     = new PHPParser_Parser(new PHPParser_Lexer);
$nodeDumper = new PHPParser_NodeDumper;

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

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

The above output will have an output looking roughly like this:

```
array(
    0: Stmt_Function(
        byRef: false
        params: array(
            0: Param(
                name: msg
                default: null
                type: null
                byRef: false
            )
        )
        stmts: array(
            0: Stmt_Echo(
                exprs: array(
                    0: Expr_Variable(
                        name: msg
                    )
                    1: Scalar_String(
                        value:

                    )
                )
            )
        )
        name: printLine
    )
    1: Expr_FuncCall(
        name: Name(
            parts: array(
                0: printLine
            )
        )
        args: array(
            0: Arg(
                value: Scalar_String(
                    value: Hallo World!!!
                )
                byRef: false
            )
        )
    )
)
```

Serialization to XML
--------------------

It is also possible to serialize the node tree to XML using `PHPParser_Serializer_XML->serialize()`
and to unserialize it using `PHPParser_Unserializer_XML->unserialize()`. This is useful for
interfacing with other languages and applications or for doing transformation using XSLT.

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

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

$parser     = new PHPParser_Parser(new PHPParser_Lexer);
$serializer = new PHPParser_Serializer_XML;

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

    echo '<pre>' . htmlspecialchars($serializer->serialize($stmts)) . '</pre>';
} catch (PHPParser_Error $e) {
    echo 'Parse Error: ', $e->getMessage();
}
```

Produces:

```xml
<?xml version="1.0" encoding="UTF-8"?>
<AST xmlns:node="http://nikic.github.com/PHPParser/XML/node" xmlns:subNode="http://nikic.github.com/PHPParser/XML/subNode" xmlns:scalar="http://nikic.github.com/PHPParser/XML/scalar">
 <scalar:array>
  <node:Stmt_Function line="2">
   <subNode:byRef>
    <scalar:false/>
   </subNode:byRef>
   <subNode:params>
    <scalar:array>
     <node:Param line="2">
      <subNode:name>
       <scalar:string>msg</scalar:string>
      </subNode:name>
      <subNode:default>
       <scalar:null/>
      </subNode:default>
      <subNode:type>
       <scalar:null/>
      </subNode:type>
      <subNode:byRef>
       <scalar:false/>
      </subNode:byRef>
     </node:Param>
    </scalar:array>
   </subNode:params>
   <subNode:stmts>
    <scalar:array>
     <node:Stmt_Echo line="3">
      <subNode:exprs>
       <scalar:array>
        <node:Expr_Variable line="3">
         <subNode:name>
          <scalar:string>msg</scalar:string>
         </subNode:name>
        </node:Expr_Variable>
        <node:Scalar_String line="3">
         <subNode:value>
          <scalar:string>
</scalar:string>
         </subNode:value>
        </node:Scalar_String>
       </scalar:array>
      </subNode:exprs>
     </node:Stmt_Echo>
    </scalar:array>
   </subNode:stmts>
   <subNode:name>
    <scalar:string>printLine</scalar:string>
   </subNode:name>
  </node:Stmt_Function>
  <node:Expr_FuncCall line="6">
   <subNode:name>
    <node:Name line="6">
     <subNode:parts>
      <scalar:array>
       <scalar:string>printLine</scalar:string>
      </scalar:array>
     </subNode:parts>
    </node:Name>
   </subNode:name>
   <subNode:args>
    <scalar:array>
     <node:Arg line="6">
      <subNode:value>
       <node:Scalar_String line="6">
        <subNode:value>
         <scalar:string>Hallo World!!!</scalar:string>
        </subNode:value>
       </node:Scalar_String>
      </subNode:value>
      <subNode:byRef>
       <scalar:false/>
      </subNode:byRef>
     </node:Arg>
    </scalar:array>
   </subNode:args>
  </node:Expr_FuncCall>
 </scalar:array>
</AST>
```