4 * This file is part of LyX, the document processor.
5 * Licence details can be found in the file COPYING.
7 * \author Alejandro Aguilar Sierra
8 * \author Lars Gullik Bjønnes
10 * Full author contact details are available in file CREDITS.
13 // Generalized simple lexical analizer.
14 // It can be used for simple syntax parsers, like lyxrc,
15 // texclass and others to come.
20 #include "support/strfwd.h"
25 namespace support { class FileName; }
27 /** A helper structure to describe a keyword for the Lexer.
28 Usually used bundled in C style arrays and passed to the
29 Lexer using a LexerKeywordTable object.
33 /// the string to be recognized
35 /// a corresponding numerical id
40 /** Generalized simple lexical analizer.
41 Use the method isOK() to check if there is still data available
42 for lexing. Use one of the the operators void* or ! to test if
43 the last reading operation was successful.
47 int readParam(LyxLex & lex)
49 int param = 1; // default value
50 if (lex.isOK()) { // the lexer has data to read
51 int p; // temporary variable
54 param = p; // only use the input if reading was successful
59 @see LyXRC.cpp for an example of usage.
64 /// initialize Lexer with no special keywords.
66 /// initialize Lexer with a bunch of keywords
67 template<int N> Lexer(LexerKeyword (&table)[N])
68 : pimpl_(0), lastReadOk_(false) { init(table, N); }
85 /// stream is open and end of stream is not reached
86 /// FIXME: test also if pushToken is not empty
87 /// FIXME: the method should be renamed to something like
88 /// dataAvailable(), in order to reflect the real behavior
90 /// FIXME: The next two operators should be replaced by one method
91 /// called e.g. lastReadOk(), in order to reflect the real
93 /// last read operation was successful.
94 operator void const *() const;
95 /// last read operation was not successful
96 bool operator!() const;
97 /// return true if able to open file, else false
98 bool setFile(support::FileName const & filename);
100 void setStream(std::istream & is);
102 std::istream & getStream();
103 /// Danger! Don't use it unless you know what you are doing.
104 void setLineNumber(int l);
105 /// Change the character that begins a comment. Default is '#'
106 void setCommentChar(char c);
108 /// returns a lex code
111 /// Read the next string, as delimited by double quotes or
112 /// whitespace. If esc is true, then we remember that some chars
113 /// might be escaped: \" at least.
114 bool next(bool esc = false);
116 /// Read next token. This one is almost the same as next(),
117 /// but it will consider " as a regular character and always
118 /// split a word if it contains a backslash.
121 /// Puts the rest of the line in the buffer, where it will
122 /// be available via getString() or getDocString().
125 /// Push a token, that next token got from lyxlex.
126 void pushToken(std::string const &);
128 /// return the current line number
129 int lineNumber() const;
132 int getInteger() const;
134 bool getBool() const;
136 double getFloat() const;
138 std::string const getString(bool trim = false) const;
140 docstring const getDocString(bool trim = false) const;
141 /** Get a long string, ended by the tag `endtoken'.
142 This string can span several lines. The first line
143 serves as a template for how many spaces the lines
144 are indented. This much white space is skipped from
145 each following line. This mechanism does not work
146 perfectly if you use tabs.
148 docstring getLongString(docstring const & endtoken);
150 /// Pushes a token list on a stack and replaces it with a new one.
151 template<int N> void pushTable(LexerKeyword (&table)[N])
152 { pushTable(table, N); }
154 /** Pops a token list into void and replaces it with the one now
159 /** Prints an error message with the corresponding line number
160 and file name. If message contains the substring `$$Token',
161 it is replaced with the value of GetString()
163 void printError(std::string const & message) const;
165 /// Prints the current token table on the supplied ostream.
166 void printTable(std::ostream &);
167 /// Used to dispaly context information in case of errors.
168 void setContext(std::string const & functionName);
171 Lexer & operator>>(std::string &);
172 /// extract docstring
173 Lexer & operator>>(docstring &);
175 Lexer & operator>>(double &);
177 Lexer & operator>>(int &);
178 /// extract unsigned integer
179 Lexer & operator>>(unsigned int &);
181 Lexer & operator>>(bool &);
182 /// extract first char of the string
183 Lexer & operator>>(char &);
185 /// read and check a required token
186 Lexer & operator>>(char const * required);
187 /// check for an optional token and swallow it if present.
188 bool checkFor(char const * required);
190 /// Quotes a string so that reading it again with Lexer::next(true)
191 /// gets the original string
192 static std::string quoteString(std::string const &);
193 /// Quotes a docstring so that reading it again with Lexer::next(true)
194 /// gets the original string
195 static docstring quoteString(docstring const &);
199 Lexer(Lexer const &);
200 void operator=(Lexer const &);
203 friend class PushPopHelper;
206 void init(LexerKeyword *, int);
207 void pushTable(LexerKeyword *, int);
214 mutable bool lastReadOk_;
218 /// extract something constructable from a string, i.e. a LaTeX length
220 Lexer & operator>>(Lexer & lex, T & t)
223 t = T(lex.getString());
228 /** Use to enable multiple exit points.
229 This is needed to ensure that the pop is done upon exit from methods
230 with more than one exit point or that can return as a response to
239 PushPopHelper(Lexer & l, LexerKeyword (&table)[N])
242 lex.pushTable(table, N);
252 /** Avoid wrong usage of PushPopHelper.
253 To avoid wrong usage:
254 PushPopHelper(...); // wrong
255 PushPopHelper pph(...); // right
257 #define PushPopHelper(x, y, z) unnamed_PushPopHelper;
258 // Tip gotten from Bobby Schmidt's column in C/C++ Users Journal