Allow creation and modification of scopes in GN.

tools/gn/parser.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TOOLS_GN_PARSER_H_
 #define TOOLS_GN_PARSER_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 40 matching lines @@
   // Vector must be valid for lifetime of call.
   Parser(const std::vector<Token>& tokens, Err* err);
   ~Parser();
 
   std::unique_ptr<ParseNode> ParseExpression();
 
   // Parses an expression with the given precedence or higher.
   std::unique_ptr<ParseNode> ParseExpression(int precedence);
 
   // |PrefixFunc|s used in parsing expressions.
+  std::unique_ptr<ParseNode> Block(Token token);
   std::unique_ptr<ParseNode> Literal(Token token);
   std::unique_ptr<ParseNode> Name(Token token);
   std::unique_ptr<ParseNode> Group(Token token);
   std::unique_ptr<ParseNode> Not(Token token);
   std::unique_ptr<ParseNode> List(Token token);
   std::unique_ptr<ParseNode> BlockComment(Token token);
 
   // |InfixFunc|s used in parsing expressions.
   std::unique_ptr<ParseNode> BinaryOperator(std::unique_ptr<ParseNode> left,
                                             Token token);
   std::unique_ptr<ParseNode> IdentifierOrCall(std::unique_ptr<ParseNode> left,
                                               Token token);
   std::unique_ptr<ParseNode> Assignment(std::unique_ptr<ParseNode> left,
                                         Token token);
   std::unique_ptr<ParseNode> Subscript(std::unique_ptr<ParseNode> left,
                                        Token token);
   std::unique_ptr<ParseNode> DotOperator(std::unique_ptr<ParseNode> left,
                                          Token token);
 
   // Helper to parse a comma separated list, optionally allowing trailing
   // commas (allowed in [] lists, not in function calls).
   std::unique_ptr<ListNode> ParseList(Token start_token,
                                       Token::Type stop_before,
                                       bool allow_trailing_comma);
 
   std::unique_ptr<ParseNode> ParseFile();
   std::unique_ptr<ParseNode> ParseStatement();
-  std::unique_ptr<BlockNode> ParseBlock();
+  // Expects to be passed the token corresponding to the '{' and that the
+  // current token is the one following the '{'.
+  std::unique_ptr<BlockNode> ParseBlock(Token being_brace,
+                                        BlockNode::ResultMode result_mode);
   std::unique_ptr<ParseNode> ParseCondition();
 
   // Generates a pre- and post-order traversal of the tree.
   void TraverseOrder(const ParseNode* root,
                      std::vector<const ParseNode*>* pre,
                      std::vector<const ParseNode*>* post);
 
   // Attach comments to nearby syntax.
   void AssignComments(ParseNode* file);
 
@@ skipping 31 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(Parser, Expression);
   FRIEND_TEST_ALL_PREFIXES(Parser, FunctionCall);
   FRIEND_TEST_ALL_PREFIXES(Parser, List);
   FRIEND_TEST_ALL_PREFIXES(Parser, ParenExpression);
   FRIEND_TEST_ALL_PREFIXES(Parser, UnaryOp);
 
   DISALLOW_COPY_AND_ASSIGN(Parser);
 };
 
 #endif  // TOOLS_GN_PARSER_H_