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/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
#pragma once
#include "IntStream.h"
namespace antlr4 {
/// A token has properties: text, type, line, character position in the line
/// (so we can ignore tabs), token channel, index, and source from which
/// we obtained this token.
class ANTLR4CPP_PUBLIC Token {
public:
static constexpr size_t INVALID_TYPE = 0;
/// During lookahead operations, this "token" signifies we hit rule end ATN state
/// and did not follow it despite needing to.
static constexpr size_t EPSILON = std::numeric_limits<size_t>::max() - 1;
static constexpr size_t MIN_USER_TOKEN_TYPE = 1;
static constexpr size_t EOF = IntStream::EOF;
virtual ~Token();
/// All tokens go to the parser (unless skip() is called in that rule)
/// on a particular "channel". The parser tunes to a particular channel
/// so that whitespace etc... can go to the parser on a "hidden" channel.
static constexpr size_t DEFAULT_CHANNEL = 0;
/// Anything on different channel than DEFAULT_CHANNEL is not parsed
/// by parser.
static constexpr size_t HIDDEN_CHANNEL = 1;
/**
* This is the minimum constant value which can be assigned to a
* user-defined token channel.
*
* <p>
* The non-negative numbers less than {@link #MIN_USER_CHANNEL_VALUE} are
* assigned to the predefined channels {@link #DEFAULT_CHANNEL} and
* {@link #HIDDEN_CHANNEL}.</p>
*
* @see Token#getChannel()
*/
static constexpr size_t MIN_USER_CHANNEL_VALUE = 2;
/// Get the text of the token.
virtual std::string getText() const = 0;
/// Get the token type of the token
virtual size_t getType() const = 0;
/// The line number on which the 1st character of this token was matched, line=1..n
virtual size_t getLine() const = 0;
/// The index of the first character of this token relative to the
/// beginning of the line at which it occurs, 0..n-1
virtual size_t getCharPositionInLine() const = 0;
/// Return the channel this token. Each token can arrive at the parser
/// on a different channel, but the parser only "tunes" to a single channel.
/// The parser ignores everything not on DEFAULT_CHANNEL.
virtual size_t getChannel() const = 0;
/// An index from 0..n-1 of the token object in the input stream.
/// This must be valid in order to print token streams and
/// use TokenRewriteStream.
///
/// Return INVALID_INDEX to indicate that this token was conjured up since
/// it doesn't have a valid index.
virtual size_t getTokenIndex() const = 0;
/// The starting character index of the token
/// This method is optional; return INVALID_INDEX if not implemented.
virtual size_t getStartIndex() const = 0;
/// The last character index of the token.
/// This method is optional; return INVALID_INDEX if not implemented.
virtual size_t getStopIndex() const = 0;
/// Gets the <seealso cref="TokenSource"/> which created this token.
virtual TokenSource *getTokenSource() const = 0;
/// Gets the <seealso cref="CharStream"/> from which this token was derived.
virtual CharStream *getInputStream() const = 0;
virtual std::string toString() const = 0;
};
} // namespace antlr4
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