llvm/mlir/examples/toy/Ch3/include/toy/Lexer.h

//===- Lexer.h - Lexer for the Toy language -------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements a simple Lexer for the Toy language.
//
//===----------------------------------------------------------------------===//

#ifndef TOY_LEXER_H
#define TOY_LEXER_H

#include "llvm/ADT/StringRef.h"

#include <cstdlib>
#include <memory>
#include <string>

namespace toy {

/// Structure definition a location in a file.
struct Location { … };

// List of Token returned by the lexer.
enum Token : int { … };

/// The Lexer is an abstract base class providing all the facilities that the
/// Parser expects. It goes through the stream one token at a time and keeps
/// track of the location in the file for debugging purpose.
/// It relies on a subclass to provide a `readNextLine()` method. The subclass
/// can proceed by reading the next line from the standard input or from a
/// memory mapped file.
class Lexer { … };

/// A lexer implementation operating on a buffer in memory.
class LexerBuffer final : public Lexer { … };
} // namespace toy

#endif // TOY_LEXER_H