86 lines
3.8 KiB
C
86 lines
3.8 KiB
C
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/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
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* Use of this file is governed by the BSD 3-clause license that
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* can be found in the LICENSE.txt file in the project root.
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*/
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#pragma once
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#include "TokenFactory.h"
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namespace antlr4 {
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/// <summary>
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/// A source of tokens must provide a sequence of tokens via <seealso cref="#nextToken()"/>
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/// and also must reveal it's source of characters; <seealso cref="CommonToken"/>'s text is
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/// computed from a <seealso cref="CharStream"/>; it only store indices into the char
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/// stream.
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/// <p/>
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/// Errors from the lexer are never passed to the parser. Either you want to keep
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/// going or you do not upon token recognition error. If you do not want to
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/// continue lexing then you do not want to continue parsing. Just throw an
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/// exception not under <seealso cref="RecognitionException"/> and Java will naturally toss
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/// you all the way out of the recognizers. If you want to continue lexing then
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/// you should not throw an exception to the parser--it has already requested a
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/// token. Keep lexing until you get a valid one. Just report errors and keep
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/// going, looking for a valid token.
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/// </summary>
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class ANTLR4CPP_PUBLIC TokenSource {
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public:
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virtual ~TokenSource();
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/// Return a <seealso cref="Token"/> object from your input stream (usually a
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/// <seealso cref="CharStream"/>). Do not fail/return upon lexing error; keep chewing
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/// on the characters until you get a good one; errors are not passed through
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/// to the parser.
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virtual std::unique_ptr<Token> nextToken() = 0;
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/// <summary>
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/// Get the line number for the current position in the input stream. The
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/// first line in the input is line 1.
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/// </summary>
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/// <returns> The line number for the current position in the input stream, or
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/// 0 if the current token source does not track line numbers. </returns>
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virtual size_t getLine() const = 0;
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/// <summary>
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/// Get the index into the current line for the current position in the input
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/// stream. The first character on a line has position 0.
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/// </summary>
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/// <returns> The line number for the current position in the input stream, or
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/// (sze_t)-1 if the current token source does not track character positions. </returns>
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virtual size_t getCharPositionInLine() = 0;
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/// <summary>
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/// Get the <seealso cref="CharStream"/> from which this token source is currently
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/// providing tokens.
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/// </summary>
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/// <returns> The <seealso cref="CharStream"/> associated with the current position in
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/// the input, or {@code null} if no input stream is available for the token
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/// source. </returns>
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virtual CharStream* getInputStream() = 0;
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/// <summary>
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/// Gets the name of the underlying input source. This method returns a
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/// non-null, non-empty string. If such a name is not known, this method
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/// returns <seealso cref="IntStream#UNKNOWN_SOURCE_NAME"/>.
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/// </summary>
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virtual std::string getSourceName() = 0;
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/// <summary>
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/// Set the <seealso cref="TokenFactory"/> this token source should use for creating
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/// <seealso cref="Token"/> objects from the input.
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/// </summary>
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/// <param name="factory"> The <seealso cref="TokenFactory"/> to use for creating tokens. </param>
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template<typename T1>
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void setTokenFactory(TokenFactory<T1> * /*factory*/) {}
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/// <summary>
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/// Gets the <seealso cref="TokenFactory"/> this token source is currently using for
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/// creating <seealso cref="Token"/> objects from the input.
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/// </summary>
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/// <returns> The <seealso cref="TokenFactory"/> currently used by this token source. </returns>
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virtual Ref<TokenFactory<CommonToken>> getTokenFactory() = 0;
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};
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} // namespace antlr4
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