comparison vendor/nikic/php-parser/doc/3_Other_node_tree_representations.markdown @ 0:4c8ae668cc8c

Initial import (non-working)

+Other node tree representations
+===============================
+
+It is possible to convert the AST into 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 quickly. The main application thus is in caching.
+
+Human readable dumping
+----------------------
+
+Furthermore it is possible to dump nodes into a human readable format using the `dump` method of
+`PhpParser\NodeDumper`. This can be used for debugging.
+
+```php
+$code = <<<'CODE'
+<?php
+
+function printLine($msg) {
+    echo $msg, "\n";
+}
+
+printLine('Hello World!!!');
+CODE;
+
+$parser = (new PhpParser\ParserFactory)->create(PhpParser\ParserFactory::PREFER_PHP7);
+$nodeDumper = new PhpParser\NodeDumper;
+
+try {
+    $stmts = $parser->parse($code);
+
+    echo $nodeDumper->dump($stmts), "\n";
+} catch (PhpParser\Error $e) {
+    echo 'Parse Error: ', $e->getMessage();
+}
+```
+
+The above script will have an output looking roughly like this:
+
+```
+array(
+    0: Stmt_Function(
+        byRef: false
+        params: array(
+            0: Param(
+                name: msg
+                default: null
+                type: null
+                byRef: false
+            )
+        )
+        stmts: array(
+            0: Stmt_Echo(
+                exprs: array(
+                    0: Expr_Variable(
+                        name: msg
+                    )
+                    1: Scalar_String(
+                        value:
+
+                    )
+                )
+            )
+        )
+        name: printLine
+    )
+    1: Expr_FuncCall(
+        name: Name(
+            parts: array(
+                0: printLine
+            )
+        )
+        args: array(
+            0: Arg(
+                value: Scalar_String(
+                    value: Hello World!!!
+                )
+                byRef: false
+            )
+        )
+    )
+)
+```
+
+JSON encoding
+-------------
+
+Nodes (and comments) implement the `JsonSerializable` interface. As such, it is possible to JSON
+encode the AST directly using `json_encode()`:
+
+```php
+$code = <<<'CODE'
+<?php
+
+function printLine($msg) {
+    echo $msg, "\n";
+}
+
+printLine('Hello World!!!');
+CODE;
+
+$parser = (new PhpParser\ParserFactory)->create(PhpParser\ParserFactory::PREFER_PHP7);
+$nodeDumper = new PhpParser\NodeDumper;
+
+try {
+    $stmts = $parser->parse($code);
+
+    echo json_encode($stmts, JSON_PRETTY_PRINT), "\n";
+} catch (PhpParser\Error $e) {
+    echo 'Parse Error: ', $e->getMessage();
+}
+```
+
+This will result in the following output (which includes attributes):
+
+```json
+[
+    {
+        "nodeType": "Stmt_Function",
+        "byRef": false,
+        "name": "printLine",
+        "params": [
+            {
+                "nodeType": "Param",
+                "type": null,
+                "byRef": false,
+                "variadic": false,
+                "name": "msg",
+                "default": null,
+                "attributes": {
+                    "startLine": 3,
+                    "endLine": 3
+                }
+            }
+        ],
+        "returnType": null,
+        "stmts": [
+            {
+                "nodeType": "Stmt_Echo",
+                "exprs": [
+                    {
+                        "nodeType": "Expr_Variable",
+                        "name": "msg",
+                        "attributes": {
+                            "startLine": 4,
+                            "endLine": 4
+                        }
+                    },
+                    {
+                        "nodeType": "Scalar_String",
+                        "value": "\n",
+                        "attributes": {
+                            "startLine": 4,
+                            "endLine": 4,
+                            "kind": 2
+                        }
+                    }
+                ],
+                "attributes": {
+                    "startLine": 4,
+                    "endLine": 4
+                }
+            }
+        ],
+        "attributes": {
+            "startLine": 3,
+            "endLine": 5
+        }
+    },
+    {
+        "nodeType": "Expr_FuncCall",
+        "name": {
+            "nodeType": "Name",
+            "parts": [
+                "printLine"
+            ],
+            "attributes": {
+                "startLine": 7,
+                "endLine": 7
+            }
+        },
+        "args": [
+            {
+                "nodeType": "Arg",
+                "value": {
+                    "nodeType": "Scalar_String",
+                    "value": "Hello World!!!",
+                    "attributes": {
+                        "startLine": 7,
+                        "endLine": 7,
+                        "kind": 1
+                    }
+                },
+                "byRef": false,
+                "unpack": false,
+                "attributes": {
+                    "startLine": 7,
+                    "endLine": 7
+                }
+            }
+        ],
+        "attributes": {
+            "startLine": 7,
+            "endLine": 7
+        }
+    }
+]
+```
+
+There is currently no mechanism to convert JSON back into a node tree. Furthermore, not all ASTs
+can be JSON encoded. In particular, JSON only supports UTF-8 strings.
+
+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 $msg, "\n";
+}
+
+printLine('Hello World!!!');
+CODE;
+
+$parser = (new PhpParser\ParserFactory)->create(PhpParser\ParserFactory::PREFER_PHP7);
+$serializer = new PhpParser\Serializer\XML;
+
+try {
+    $stmts = $parser->parse($code);
+
+    echo $serializer->serialize($stmts);
+} 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>Hello 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>
+```