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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 "TokenFactory.h"
namespace antlr4 {
/// <summary>
/// A source of tokens must provide a sequence of tokens via <seealso cref="#nextToken()"/>
/// and also must reveal it's source of characters; <seealso cref="CommonToken"/>'s text is
/// computed from a <seealso cref="CharStream"/>; it only store indices into the char
/// stream.
/// <p/>
/// Errors from the lexer are never passed to the parser. Either you want to keep
/// going or you do not upon token recognition error. If you do not want to
/// continue lexing then you do not want to continue parsing. Just throw an
/// exception not under <seealso cref="RecognitionException"/> and Java will naturally toss
/// you all the way out of the recognizers. If you want to continue lexing then
/// you should not throw an exception to the parser--it has already requested a
/// token. Keep lexing until you get a valid one. Just report errors and keep
/// going, looking for a valid token.
/// </summary>
class ANTLR4CPP_PUBLIC TokenSource {
public:
virtual ~TokenSource();
/// Return a <seealso cref="Token"/> object from your input stream (usually a
/// <seealso cref="CharStream"/>). Do not fail/return upon lexing error; keep chewing
/// on the characters until you get a good one; errors are not passed through
/// to the parser.
virtual std::unique_ptr<Token> nextToken() = 0;
/// <summary>
/// Get the line number for the current position in the input stream. The
/// first line in the input is line 1.
/// </summary>
/// <returns> The line number for the current position in the input stream, or
/// 0 if the current token source does not track line numbers. </returns>
virtual size_t getLine() const = 0;
/// <summary>
/// Get the index into the current line for the current position in the input
/// stream. The first character on a line has position 0.
/// </summary>
/// <returns> The line number for the current position in the input stream, or
/// (sze_t)-1 if the current token source does not track character positions. </returns>
virtual size_t getCharPositionInLine() = 0;
/// <summary>
/// Get the <seealso cref="CharStream"/> from which this token source is currently
/// providing tokens.
/// </summary>
/// <returns> The <seealso cref="CharStream"/> associated with the current position in
/// the input, or {@code null} if no input stream is available for the token
/// source. </returns>
virtual CharStream* getInputStream() = 0;
/// <summary>
/// Gets the name of the underlying input source. This method returns a
/// non-null, non-empty string. If such a name is not known, this method
/// returns <seealso cref="IntStream#UNKNOWN_SOURCE_NAME"/>.
/// </summary>
virtual std::string getSourceName() = 0;
/// <summary>
/// Set the <seealso cref="TokenFactory"/> this token source should use for creating
/// <seealso cref="Token"/> objects from the input.
/// </summary>
/// <param name="factory"> The <seealso cref="TokenFactory"/> to use for creating tokens. </param>
template<typename T1>
void setTokenFactory(TokenFactory<T1> * /*factory*/) {}
/// <summary>
/// Gets the <seealso cref="TokenFactory"/> this token source is currently using for
/// creating <seealso cref="Token"/> objects from the input.
/// </summary>
/// <returns> The <seealso cref="TokenFactory"/> currently used by this token source. </returns>
virtual TokenFactory<CommonToken>* getTokenFactory() = 0;
};
} // namespace antlr4
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