4 * (C) Copyright 2014, Stephen M. Cameron.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 struct parser_value_type {
31 typedef union valtype {
32 struct parser_value_type v;
35 #define YYSTYPE PARSER_VALUE_TYPE
37 int yyerror(__attribute__((unused)) long long *result,
38 __attribute__((unused)) double *dresult,
39 __attribute__((unused)) int *has_error,
40 __attribute__((unused)) int *bye, const char *msg);
42 extern int yylex(void);
43 extern void yyrestart(FILE *file);
48 struct parser_value_type {
64 %parse-param { long long *result }
65 %parse-param { double *dresult }
66 %parse-param { int *has_error }
67 %parse-param { int *bye }
72 top_level: expression {
75 *has_error = $1.has_error;
82 expression: expression '+' expression {
83 if (!$1.has_dval && !$3.has_dval)
84 $$.ival = $1.ival + $3.ival;
86 $$.ival = (long long) ($1.dval + $3.dval);
87 $$.dval = $1.dval + $3.dval;
88 $$.has_error = $1.has_error || $3.has_error;
90 | expression '-' expression {
91 if (!$1.has_dval && !$3.has_dval)
92 $$.ival = $1.ival - $3.ival;
94 $$.ival = (long long) ($1.dval - $3.dval);
95 $$.dval = $1.dval - $3.dval;
96 $$.has_error = $1.has_error || $3.has_error;
98 | expression '*' expression {
99 if (!$1.has_dval && !$3.has_dval)
100 $$.ival = $1.ival * $3.ival;
102 $$.ival = (long long) ($1.dval * $3.dval);
103 $$.dval = $1.dval * $3.dval;
104 $$.has_error = $1.has_error || $3.has_error;
106 | expression '/' expression {
108 yyerror(0, 0, 0, 0, "divide by zero");
110 $$.ival = $1.ival / $3.ival;
111 if ($3.dval < 1e-20 && $3.dval > -1e-20)
112 yyerror(0, 0, 0, 0, "divide by zero");
114 $$.dval = $1.dval / $3.dval;
115 if ($3.has_dval || $1.has_dval)
116 $$.ival = (long long) $$.dval;
117 $$.has_error = $1.has_error || $3.has_error;
119 | '-' expression %prec UMINUS {
122 $$.has_error = $2.has_error;
124 | '(' expression ')' { $$ = $2; }
125 | expression SUFFIX {
126 if (!$1.has_dval && !$2.has_dval)
127 $$.ival = $1.ival * $2.ival;
129 $$.ival = (long long) $1.dval * $2.dval;
130 if ($1.has_dval || $2.has_dval)
131 $$.dval = $1.dval * $2.dval;
133 $$.dval = $1.ival * $2.ival;
134 $$.has_error = $1.has_error || $2.has_error;
136 | expression '%' expression {
137 if ($1.has_dval || $3.has_dval)
138 yyerror(0, 0, 0, 0, "modulo on floats");
140 yyerror(0, 0, 0, 0, "divide by zero");
142 $$.ival = $1.ival % $3.ival;
145 $$.has_error = $1.has_error || $3.has_error;
147 | expression '^' expression {
148 $$.has_error = $1.has_error || $3.has_error;
149 if (!$1.has_dval && !$3.has_dval) {
154 } else if ($3.ival > 0) {
155 long long tmp = $1.ival;
157 for (i = 0; i < $3.ival; i++)
160 /* integers, 2^-3, ok, we now have doubles */
162 if ($1.ival == 0 && $3.ival == 0) {
166 double x = (double) $1.ival;
167 double y = (double) $3.ival;
170 $$.ival = (long long) tmp;
172 $$.dval = pow($1.dval, $3.dval);
174 $$.dval = pow($1.dval, $3.dval);
175 $$.ival = (long long) $$.dval;
178 | NUMBER { $$ = $1; }
179 | BYE { $$ = $1; *bye = 1; };
183 /* Urgh. yacc and lex are kind of horrible. This is not thread safe, obviously. */
184 static int lexer_read_offset = 0;
185 static char lexer_input_buffer[1000];
187 int lexer_input(char* buffer, int *bytes_read, int bytes_requested)
189 int bytes_left = strlen(lexer_input_buffer) - lexer_read_offset;
191 if (bytes_requested > bytes_left )
192 bytes_requested = bytes_left;
193 memcpy(buffer, &lexer_input_buffer[lexer_read_offset], bytes_requested);
194 *bytes_read = bytes_requested;
195 lexer_read_offset += bytes_requested;
199 static void setup_to_parse_string(const char *string)
203 len = strlen(string);
204 if (len > sizeof(lexer_input_buffer) - 3)
205 len = sizeof(lexer_input_buffer) - 3;
207 strncpy(lexer_input_buffer, string, len);
208 lexer_input_buffer[len] = '\0';
209 lexer_input_buffer[len + 1] = '\0'; /* lex/yacc want string double null terminated! */
210 lexer_read_offset = 0;
213 int evaluate_arithmetic_expression(const char *buffer, long long *ival, double *dval)
215 int rc, bye = 0, has_error = 0;
217 setup_to_parse_string(buffer);
218 rc = yyparse(ival, dval, &has_error, &bye);
220 if (rc || bye || has_error) {
228 int yyerror(__attribute__((unused)) long long *result,
229 __attribute__((unused)) double *dresult,
230 __attribute__((unused)) int *has_error,
231 __attribute__((unused)) int *bye, const char *msg)
233 fprintf(stderr, "%s\n", msg);