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/*
Ousía
Copyright (C) 2014 Benjamin Paaßen, Andreas Stöckel
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _OUSIA_UTILS_CODE_TOKENIZER_HPP_
#define _OUSIA_UTILS_CODE_TOKENIZER_HPP_
#include <map>
#include <sstream>
#include "BufferedCharReader.hpp"
#include "Tokenizer.hpp"
namespace ousia {
namespace utils {
/*
* This enum contains all special Token the CodeTokenizer supports, namely:
*
* 1.) An ambigous Tokens - in post programming languages single-quotes ' or
* double-quotes " - to delimit string tokens.
* 2.) A start token for line comments, which would e.g. be // in Java.
* 3.) A start token for a block comment
* 4.) An end token for a block comment.
* 5.) A linebreak token
* 6.) The escape token, which would e.g. be \ in java.
*/
enum class CodeTokenMode {
STRING_START_END,
LINE_COMMENT,
BLOCK_COMMENT_START,
BLOCK_COMMENT_END,
LINEBREAK,
ESCAPE,
NONE
};
/**
* A CodeTokenDescriptor defines the id the user likes to have returned for
* a Token of the mode specified, e.g. if you want to get the id 4 for a
* String Token the corresponding CodeTokenDescriptor would be inizialized
* with CodeTokenDescriptor myDesc {CodeTokenMode::STRING_START_END, 4};
*/
struct CodeTokenDescriptor {
CodeTokenMode mode;
int id;
CodeTokenDescriptor(CodeTokenMode mode, int id) : mode(mode), id(id) {}
};
/**
* The CodeTokenizer is a finite state machine with the states NORMAL, being
* IN_BLOCK_COMMENT, being IN_LINE_COMMENT or being IN_STRING.
*/
enum class CodeTokenizerState {
NORMAL,
IN_BLOCK_COMMENT,
IN_LINE_COMMENT,
IN_STRING
};
/**
* The purpose of a CodeTokenizer is to make it easier to parse classical
* programming Code. It adds the following features to a regular Tokenizer:
* 1.) String tokens (e.g. "string" in Java Code) instead of 3 separate tokens
* for the opening delimiter, the text and the closing delimiter.
* 2.) Escaping in String tokens.
* 3.) Comment Tokens (for line comments as well as block comments)
*/
class CodeTokenizer : public Tokenizer {
private:
std::map<int, CodeTokenDescriptor> descriptors;
CodeTokenizerState state;
std::stringstream buf;
Token startToken;
int returnTokenId;
bool escaped = false;
Token constructToken(const Token &t);
void buffer(const Token &t);
protected:
bool doPrepare(const Token &t, std::deque<Token> &peeked) override;
public:
/**
* If you do not want comment tokens to be returned you can set this to
* true.
*/
bool ignoreComments = false;
/**
*
* @param input a BufferedCharReader containing the input for this
*tokenizer,
* as with a regular tokenizer.
* @param root a TokenTreeNode representing the root of the TokenTree.
* Please note that you have to specify all tokenIDs here that you use
* in the descriptors map.
* @param descriptors a map mapping tokenIDs to CodeTokenDescriptors.
* In this way you can specify the meaning of certain Tokens. Say you
* specified the Token "//" with the id 1 in the TokenTree. Then you could
* add the entry "1" with the Mode "LINE_COMMENT" to the descriptors map
* and this CodeTokenizer would recognize the token "//" as starting a
* line comment.
*/
CodeTokenizer(BufferedCharReader &input, const TokenTreeNode &root,
std::map<int, CodeTokenDescriptor> descriptors)
: Tokenizer(input, root), descriptors(descriptors), state(CodeTokenizerState::NORMAL)
{
}
};
}
}
#endif
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