0a7bbec03e80bfec631ba2b33eb7048b66023118
[ginac.git] / 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