comparison vendor/nikic/php-parser/doc/component/JSON_representation.markdown @ 13:5fb285c0d0e3

Update Drupal core to 8.4.7 via Composer. Security update; I *think* we've
been lucky to get away with this so far, as we don't support self-registration
which seems to be used by the so-called "drupalgeddon 2" attack that 8.4.5
was vulnerable to.

+JSON representation
+===================
+
+Nodes (and comments) implement the `JsonSerializable` interface. As such, it is possible to JSON
+encode the AST directly using `json_encode()`:
+
+```php
+<?php
+
+use PhpParser\ParserFactory;
+
+$code = <<<'CODE'
+<?php
+
+/** @param string $msg */
+function printLine($msg) {
+    echo $msg, "\n";
+}
+CODE;
+
+$parser = (new ParserFactory)->create(ParserFactory::PREFER_PHP7);
+
+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": {
+            "nodeType": "Identifier",
+            "name": "printLine",
+            "attributes": {
+                "startLine": 4,
+                "endLine": 4
+            }
+        },
+        "params": [
+            {
+                "nodeType": "Param",
+                "type": null,
+                "byRef": false,
+                "variadic": false,
+                "var": {
+                    "nodeType": "Expr_Variable",
+                    "name": "msg",
+                    "attributes": {
+                        "startLine": 4,
+                        "endLine": 4
+                    }
+                },
+                "default": null,
+                "attributes": {
+                    "startLine": 4,
+                    "endLine": 4
+                }
+            }
+        ],
+        "returnType": null,
+        "stmts": [
+            {
+                "nodeType": "Stmt_Echo",
+                "exprs": [
+                    {
+                        "nodeType": "Expr_Variable",
+                        "name": "msg",
+                        "attributes": {
+                            "startLine": 5,
+                            "endLine": 5
+                        }
+                    },
+                    {
+                        "nodeType": "Scalar_String",
+                        "value": "\n",
+                        "attributes": {
+                            "startLine": 5,
+                            "endLine": 5,
+                            "kind": 2
+                        }
+                    }
+                ],
+                "attributes": {
+                    "startLine": 5,
+                    "endLine": 5
+                }
+            }
+        ],
+        "attributes": {
+            "startLine": 4,
+            "comments": [
+                {
+                    "nodeType": "Comment_Doc",
+                    "text": "\/** @param string $msg *\/",
+                    "line": 3,
+                    "filePos": 9,
+                    "tokenPos": 2
+                }
+            ],
+            "endLine": 6
+        }
+    }
+]
+```
+
+The JSON representation may be converted back into an AST using the `JsonDecoder`:
+
+```php
+<?php
+
+$nodeDecoder = new PhpParser\NodeDecoder();
+$ast = $nodeDecoder->decode($json);
+```
+
+Note that not all ASTs can be represented using JSON. In particular:
+
+ * JSON only supports UTF-8 strings.
+ * JSON does not support non-finite floating-point numbers. This can occur if the original source
+   code contains non-representable floating-pointing literals such as `1e1000`.
+
+If the node tree is not representable in JSON, the initial `json_encode()` call will fail.
+
+From the command line, a JSON dump can be obtained using `vendor/bin/php-parse -j file.php`.