text: // Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
  // Licensed under the MIT License:
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  #ifndef CAPNP_COMPILER_LEXER_H_
  #define CAPNP_COMPILER_LEXER_H_
  
  #if defined(__GNUC__) && !defined(CAPNP_HEADER_WARNINGS)
  #pragma GCC system_header
  #endif
  
  #include <capnp/compiler/lexer.capnp.h>
  #include <kj/parse/common.h>
  #include <kj/arena.h>
  #include "error-reporter.h"
  
  namespace capnp {
  namespace compiler {
  
  bool lex(kj::ArrayPtr<const char> input, LexedStatements::Builder result,
           ErrorReporter& errorReporter);
  bool lex(kj::ArrayPtr<const char> input, LexedTokens::Builder result, ErrorReporter& errorReporter);
  // Lex the given source code, placing the results in `result`.  Returns true if there
  // were no errors, false if there were.  Even when errors are present, the file may have partial
  // content which can be fed into later stages of parsing in order to find more errors.
  //
  // There are two versions, one that parses a list of statements, and one which just parses tokens
  // that might form a part of one statement.  In other words, in the later case, the input should
  // not contain semicolons or curly braces, unless they are in string literals of course.
  
  class Lexer {
    // Advanced lexer interface.  This interface exposes the inner parsers so that you can embed them
    // into your own parsers.
  
  public:
    Lexer(Orphanage orphanage, ErrorReporter& errorReporter);
    // `orphanage` is used to allocate Cap'n Proto message objects in the result.  `inputStart` is
    // a pointer to the beginning of the input, used to compute byte offsets.
  
    ~Lexer() noexcept(false);
  
    class ParserInput: public kj::parse::IteratorInput<char, const char*> {
      // Like IteratorInput<char, const char*> except that positions are measured as byte offsets
      // rather than pointers.
  
    public:
      ParserInput(const char* begin, const char* end)
        : IteratorInput<char, const char*>(begin, end), begin(begin) {}
      explicit ParserInput(ParserInput& parent)
        : IteratorInput<char, const char*>(parent), begin(parent.begin) {}
  
      inline uint32_t getBest() {
        return IteratorInput<char, const char*>::getBest() - begin;
      }
      inline uint32_t getPosition() {
        return IteratorInput<char, const char*>::getPosition() - begin;
      }
  
    private:
      const char* begin;
    };
  
    template <typename Output>
    using Parser = kj::parse::ParserRef<ParserInput, Output>;
  
    struct Parsers {
      Parser<kj::Tuple<>> emptySpace;
      Parser<Orphan<Token>> token;
      Parser<kj::Array<Orphan<Token>>> tokenSequence;
      Parser<Orphan<Statement>> statement;
      Parser<kj::Array<Orphan<Statement>>> statementSequence;
    };
  
    const Parsers& getParsers() { return parsers; }
  
  private:
    Orphanage orphanage;
    kj::Arena arena;
    Parsers parsers;
  };
  
  }  // namespace compiler
  }  // namespace capnp
  
  #endif  // CAPNP_COMPILER_LEXER_H_
  