//===--- LexerState.h - Lexer State -----------------------------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
//  This file defines the LexerState object.
//
//===----------------------------------------------------------------------===//

#ifndef SWIFT_LEXERSTATE_H
#define SWIFT_LEXERSTATE_H

#include "llvm/ADT/Optional.h"
#include "swift/Basic/SourceLoc.h"
#include "swift/Syntax/Trivia.h"

namespace swift {
class Lexer;

/// \brief Lexer state can be saved/restored to/from objects of this class.
class LexerState {
public:
  LexerState() {}

  bool isValid() const { return Loc.isValid(); }

  LexerState advance(unsigned Offset) const {
    assert(isValid());
    return LexerState(Loc.getAdvancedLoc(Offset));
  }

private:
  explicit LexerState(SourceLoc Loc) : Loc(Loc) {}
  SourceLoc Loc;
  llvm::Optional<syntax::Trivia> LeadingTrivia;
  friend class Lexer;
};

} // end namespace swift

#endif