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// 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 <vector>
#include "base/basictypes.h"
#include "base/gtest_prod_util.h"
#include "base/memory/scoped_ptr.h"
#include "tools/gn/err.h"
#include "tools/gn/parse_tree.h"
// Parses a series of tokens. The resulting AST will refer to the tokens passed
// to the input, so the tokens an the file data they refer to must outlive your
// use of the ParseNode.
class Parser {
public:
// Will return a null pointer and set the err on error.
static scoped_ptr<ParseNode> Parse(const std::vector<Token>& tokens,
Err* err);
// Alternative to parsing that assumes the input is an expression.
static scoped_ptr<ParseNode> ParseExpression(const std::vector<Token>& tokens,
Err* err);
private:
// Vector must be valid for lifetime of call.
Parser(const std::vector<Token>& tokens, Err* err);
~Parser();
scoped_ptr<AccessorNode> ParseAccessor();
scoped_ptr<BlockNode> ParseBlock(bool need_braces);
scoped_ptr<ConditionNode> ParseCondition();
scoped_ptr<ParseNode> ParseExpression();
scoped_ptr<ParseNode> ParseExpressionExceptBinaryOperators();
scoped_ptr<FunctionCallNode> ParseFunctionCall();
scoped_ptr<ListNode> ParseList(const Token& expected_begin,
const Token& expected_end);
scoped_ptr<ParseNode> ParseParenExpression();
scoped_ptr<UnaryOpNode> ParseUnaryOp();
bool IsToken(Token::Type type, char* str) const;
// Gets an error corresponding to the last token. When we hit an EOF
// usually we've already gone beyond the end (or maybe there are no tokens)
// so there is some tricky logic to report this.
Err MakeEOFError(const std::string& message,
const std::string& help = std::string()) const;
const Token& cur_token() const { return tokens_[cur_]; }
bool done() const { return at_end() || has_error(); }
bool at_end() const { return cur_ >= tokens_.size(); }
bool has_error() const { return err_->has_error(); }
const Token& next_token() const { return tokens_[cur_ + 1]; }
bool has_next_token() const { return cur_ + 1 < tokens_.size(); }
const std::vector<Token>& tokens_;
Err* err_;
// Current index into the tokens.
size_t cur_;
FRIEND_TEST_ALL_PREFIXES(Parser, BinaryOp);
FRIEND_TEST_ALL_PREFIXES(Parser, Block);
FRIEND_TEST_ALL_PREFIXES(Parser, Condition);
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_
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