Add ast_dump() option AST_DUMP_EXCLUDE_DOC_COMMENT (nikic#192)

Closes nikic#191.

Author: fan-y-mishiba2

tests/ast_dump_with_exclude_doc.phpt

@@ -0,0 +1,38 @@
+--TEST--
+ast_dump() with AST_DUMP_EXCLUDE_DOC_COMMENT
+--FILE--
+<?php
+
+require __DIR__ . '/../util.php';
+
+$code = <<<'PHP'
+<?php
+/**
+ * test
+ * @param mixed $foo
+ * @return void
+ */
+function test($foo) {
+}
+PHP;
+
+$ast = ast\parse_code($code, $version=80);
+echo ast_dump($ast, AST_DUMP_EXCLUDE_DOC_COMMENT);
+
+?>
+--EXPECT--
+AST_STMT_LIST
+    0: AST_FUNC_DECL
+        flags: 0
+        name: "test"
+        params: AST_PARAM_LIST
+            0: AST_PARAM
+                flags: 0
+                type: null
+                name: "foo"
+                default: null
+                attributes: null
+        stmts: AST_STMT_LIST
+        returnType: null
+        attributes: null
+        __declId: 0

util.php

@@ -3,6 +3,7 @@
 use ast\flags;
 
 const AST_DUMP_LINENOS = 1;
+const AST_DUMP_EXCLUDE_DOC_COMMENT = 2;
 
 function get_flag_info() : array {
     static $info;
@@ -65,13 +66,16 @@ function ast_dump($ast, int $options = 0) : string {
             $result .= "\n    flags: " . format_flags($ast->kind, $ast->flags);
         }
         foreach ($ast->children as $i => $child) {
+            if (($options & AST_DUMP_EXCLUDE_DOC_COMMENT) && $i === 'docComment') {
+                continue;
+            }
             $result .= "\n    $i: " . str_replace("\n", "\n    ", ast_dump($child, $options));
         }
         return $result;
     } else if ($ast === null) {
         return 'null';
     } else if (is_string($ast)) {
-        return "\"$ast\""; 
+        return "\"$ast\"";
     } else {
         return (string) $ast;
     }