src/lyxlex.h

   1 // -*- C++ -*-
   2 /**
   3  * \file lyxlex.h
   4  * This file is part of LyX, the document processor.
   5  * Licence details can be found in the file COPYING.
   6  *
   7  * \author Alejandro Aguilar Sierra
   8  * \author Lars Gullik Bjønnes
   9  *
  10  * Full author contact details are available in file CREDITS.
  11  */
  12
  13 //  Generalized simple lexical analizer.
  14 //  It can be used for simple syntax parsers, like lyxrc,
  15 //  texclass and others to come.
  16
  17 #ifndef LYXLEX_H
  18 #define LYXLEX_H
  19
  20 #include <boost/utility.hpp>
  21
  22 #include <iosfwd>
  23 #include <string>
  24
  25
  26 ///
  27 struct keyword_item {
  28         ///
  29         char const * tag;
  30         ///
  31         int code;
  32 };
  33
  34 /** Generalized simple lexical analizer.
  35     It can be used for simple syntax parsers, like lyxrc,
  36     texclass and others to come.
  37     @see lyxrc.C for an example of usage.
  38   */
  39 class LyXLex : boost::noncopyable {
  40 public:
  41         ///
  42         LyXLex(keyword_item *, int);
  43         ///
  44         ~LyXLex();
  45
  46         /// Lex basic codes
  47         enum {
  48                 ///
  49                 LEX_UNDEF = -1,
  50                 ///
  51                 LEX_FEOF  = -2,
  52                 ///
  53                 LEX_DATA  = -3,
  54                 ///
  55                 LEX_TOKEN = -4
  56         };
  57
  58         /// stream is open and end of stream is not reached
  59         bool isOK() const;
  60         /// stream is ok
  61         operator void const *() const;
  62         /// stream is not ok
  63         bool operator!() const;
  64         /// return true if able to open file, else false
  65         bool setFile(std::string const & filename);
  66         ///
  67         void setStream(std::istream & is);
  68         ///
  69         std::istream & getStream();
  70         /// Danger! Don't use it unless you know what you are doing.
  71         void setLineNo(int l);
  72         /// Change the character that begins a comment. Default is '#'
  73         void setCommentChar(char c);
  74
  75         /// returns a lex code
  76         int lex();
  77
  78         /** Just read athe next word. If esc is true remember that
  79             some chars might be escaped: "\ atleast
  80         */
  81         bool next(bool esc = false);
  82
  83         /** Read next token. This one is almost the same as next,
  84             but it will consider " as a regular character and always
  85             split a word if it contains a backslash.
  86         */
  87         bool nextToken();
  88         /// Push a token, that next token got from lyxlex.
  89         void pushToken(std::string const &);
  90
  91         ///
  92         int getLineNo() const;
  93
  94         ///
  95         int getInteger() const;
  96         ///
  97         bool getBool() const;
  98         ///
  99         float getFloat() const;
 100         ///
 101         std::string const getString() const;
 102
 103         /** Get a long string, ended by the tag `endtag'.
 104             This string can span several lines. The first line
 105             serves as a template for how many spaces the lines
 106             are indented. This much white space is skipped from
 107             each following line. This mechanism does not work
 108             perfectly if you use tabs.
 109         */
 110         std::string const getLongString(std::string const & endtag);
 111
 112         ///
 113         bool eatLine();
 114
 115         /// Pushes a token list on a stack and replaces it with a new one.
 116         void pushTable(keyword_item *, int);
 117
 118         /** Pops a token list into void and replaces it with the one now
 119             on top of the stack.
 120         */
 121         void popTable();
 122
 123         /** Prints an error message with the corresponding line number
 124             and file name. If message contains the substring `$$Token',
 125             it is replaced with the value of GetString()
 126         */
 127         void printError(std::string const & message) const;
 128
 129         /// Prints the current token table on the supplied ostream.
 130         void printTable(std::ostream &);
 131
 132         /// extract string
 133         LyXLex & operator>>(std::string &);
 134         /// extract float
 135         LyXLex & operator>>(float &);
 136         /// extract double
 137         LyXLex & operator>>(double &);
 138         /// extract integer
 139         LyXLex & operator>>(int &);
 140         /// extract unsigned integer
 141         LyXLex & operator>>(unsigned int &);
 142         /// extract bool
 143         LyXLex & operator>>(bool &);
 144
 145 private:
 146         struct Pimpl;
 147         ///
 148         Pimpl * pimpl_;
 149 };
 150
 151
 152 /** Use to enable multiple exit points.
 153     This is needed to ensure that the pop is done upon exit from methods
 154     with more than one exit point or that can return as a response to
 155     exceptions.
 156     @author Lgb
 157 */
 158 struct pushpophelper {
 159         ///
 160         pushpophelper(LyXLex & lexrc, keyword_item * i, int s) : lex(lexrc) {
 161                 lex.pushTable(i, s);
 162         }
 163         ///
 164         ~pushpophelper() {
 165                 lex.popTable();
 166         }
 167         ///
 168         LyXLex & lex;
 169 };
 170 /** Avoid wrong usage of pushpophelper.
 171     To avoid wrong usage:
 172     pushpophelper(...); // wrong
 173     pushpophelper pph(...); // right
 174 */
 175 #define pushpophelper(x, y, z) unnamed_pushpophelper;
 176 // Tip gotten from Bobby Schmidt's column in C/C++ Users Journal
 177
 178 #endif