ginac/input_lexer.ll

   1 /** @file input_lexer.ll
   2  *
   3  *  Lexical analyzer definition for reading expressions.
   4  *  This file must be processed with flex. */
   5
   6 /*
   7  *  GiNaC Copyright (C) 1999-2008 Johannes Gutenberg University Mainz, Germany
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2 of the License, or
  12  *  (at your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to the Free Software
  21  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  22  */
  23
  24
  25 /*
  26  *  Definitions
  27  */
  28
  29 %pointer
  30
  31 %{
  32 #include <iostream>
  33 #include <string>
  34 #include <map>
  35 #include <stdexcept>
  36
  37 #include "input_lexer.h"
  38 #include "ex.h"
  39 #include "constant.h"
  40 #include "fail.h"
  41 #include "numeric.h"
  42 #include "symbol.h"
  43 #include "lst.h"
  44 #include "idx.h"
  45
  46 using namespace GiNaC;
  47 namespace GiNaC {
  48
  49 #include "input_parser.h"
  50
  51 } // namespace GiNaC
  52
  53 // Table of all used symbols/indices
  54 struct sym_def {
  55         sym_def() : predefined(false) {}
  56         sym_def(const ex &s, bool predef) : sym(s), predefined(predef) {}
  57         ~sym_def() {}
  58
  59         sym_def(const sym_def &other) {sym = other.sym; predefined = other.predefined;}
  60         const sym_def &operator=(const sym_def &other)
  61         {
  62                 if (this != &other) {
  63                         sym = other.sym;
  64                         predefined = other.predefined;
  65                 }
  66                 return *this;
  67         }
  68
  69         ex sym;
  70         bool predefined;        // true = user supplied symbol, false = lexer generated symbol
  71 };
  72 typedef std::map<std::string, sym_def> sym_tab;
  73 static sym_tab syms;
  74
  75 // lex input function
  76 static int lexer_input(char *buf, int max_size);
  77 #define YY_INPUT(buf, result, max_size) (result = lexer_input(buf, max_size))
  78 %}
  79
  80         /* Abbreviations */
  81 D       [0-9]
  82 E       [elEL][-+]?{D}+
  83 A       [a-zA-Z_]
  84 AN      [0-9a-zA-Z_]
  85
  86
  87 /*
  88  *  Lexical rules
  89  */
  90
  91 %%
  92 [ \t\n]+                /* skip whitespace */
  93
  94                         /* special values */
  95 Pi                      ginac_yylval = Pi; return T_LITERAL;
  96 Euler                   ginac_yylval = Euler; return T_LITERAL;
  97 Catalan                 ginac_yylval = Catalan; return T_LITERAL;
  98 FAIL                    ginac_yylval = *new fail(); return T_LITERAL;
  99 I                       ginac_yylval = I; return T_NUMBER;
 100 Digits                  ginac_yylval = (long)Digits; return T_DIGITS;
 101
 102                         /* comparison */
 103 "=="                    return T_EQUAL;
 104 "!="                    return T_NOTEQ;
 105 "<="                    return T_LESSEQ;
 106 ">="                    return T_GREATEREQ;
 107
 108                         /* numbers */
 109 {D}+                    |
 110 "#"{D}+"R"{AN}+         |
 111 "#b"([01])+             |
 112 "#o"[0-7]+              |
 113 "#x"[0-9a-fA-F]+        |
 114 {D}+"."{D}*({E})?       |
 115 {D}*"."{D}+({E})?       |
 116 {D}+{E}                 ginac_yylval = numeric(yytext); return T_NUMBER;
 117
 118                         /* symbols */
 119 {A}{AN}*                {
 120                                 sym_tab::const_iterator i = syms.find(yytext);
 121                                 if (i == syms.end()) {
 122                                         symbol tmp(yytext);
 123                                         ginac_yylval = tmp;
 124                                         syms[yytext] = sym_def(tmp, false);
 125                                 } else
 126                                         ginac_yylval = (*i).second.sym;
 127                                 return T_SYMBOL;
 128                         }
 129
 130                         /* end of input */
 131 <<EOF>>                 return T_EOF;
 132
 133                         /* everything else */
 134 .                       return *yytext;
 135
 136 %%
 137
 138
 139 /*
 140  *  Routines
 141  */
 142
 143 // The string from which we will read
 144 static std::string lexer_string;
 145
 146 // The current position within the string
 147 static int curr_pos = 0;
 148
 149 // Input function that reads from string
 150 static int lexer_input(char *buf, int max_size)
 151 {
 152         int actual = lexer_string.length() - curr_pos;
 153         if (actual > max_size)
 154                 actual = max_size;
 155         if (actual <= 0)
 156                 return YY_NULL;
 157         lexer_string.copy(buf, actual, curr_pos);
 158         curr_pos += actual;
 159         return actual;
 160 }
 161
 162 // EOF encountered, terminate the scanner
 163 int ginac_yywrap()
 164 {
 165         return 1;
 166 }
 167
 168 namespace GiNaC {
 169
 170 // Set the input string
 171 void set_lexer_string(const std::string &s)
 172 {
 173         lexer_string = s;
 174         curr_pos = 0;
 175 }
 176
 177 // Get name of symbol/index
 178 std::string get_symbol_name(const ex & s)
 179 {
 180         if (is_a<symbol>(s))
 181                 return ex_to<symbol>(s).get_name();
 182         else if (is_a<idx>(s) && is_a<symbol>(s.op(0)))
 183                 return ex_to<symbol>(s.op(0)).get_name();
 184         else
 185                 throw (std::runtime_error("get_symbol_name(): unexpected expression type"));
 186 }
 187
 188 // Set the list of predefined symbols/indices
 189 void set_lexer_symbols(ex l)
 190 {
 191         syms.clear();
 192         if (!is_exactly_a<lst>(l))
 193                 return;
 194         for (unsigned i=0; i<l.nops(); i++) {
 195                 const ex &o = l.op(i);
 196                 if (is_a<symbol>(o) || (is_a<idx>(o) && is_a<symbol>(o.op(0))))
 197                         syms[get_symbol_name(o)] = sym_def(o, true);
 198         }
 199 }
 200
 201 // Check whether symbol/index was predefined
 202 bool is_lexer_symbol_predefined(const ex &s)
 203 {
 204         sym_tab::const_iterator i = syms.find(get_symbol_name(s));
 205         if (i == syms.end())
 206                 return false;
 207         else
 208                 return (*i).second.predefined;
 209 }
 210
 211 } // namespace GiNaC