3 // ----------------------------------------------------------------------------
4 // data structures for storing the parsed expression in memory
6 typedef struct eval_value {
10 calculated_number number;
11 EVAL_VARIABLE *variable;
12 struct eval_node *expression;
16 typedef struct eval_node {
18 unsigned char operator;
25 // these are used for EVAL_NODE.operator
26 // they are used as internal IDs to identify an operator
27 // THEY ARE NOT USED FOR PARSING OPERATORS LIKE THAT
28 #define EVAL_OPERATOR_NOP '\0'
29 #define EVAL_OPERATOR_EXPRESSION_OPEN '('
30 #define EVAL_OPERATOR_EXPRESSION_CLOSE ')'
31 #define EVAL_OPERATOR_NOT '!'
32 #define EVAL_OPERATOR_PLUS '+'
33 #define EVAL_OPERATOR_MINUS '-'
34 #define EVAL_OPERATOR_AND '&'
35 #define EVAL_OPERATOR_OR '|'
36 #define EVAL_OPERATOR_GREATER_THAN_OR_EQUAL 'G'
37 #define EVAL_OPERATOR_LESS_THAN_OR_EQUAL 'L'
38 #define EVAL_OPERATOR_NOT_EQUAL '~'
39 #define EVAL_OPERATOR_EQUAL '='
40 #define EVAL_OPERATOR_LESS '<'
41 #define EVAL_OPERATOR_GREATER '>'
42 #define EVAL_OPERATOR_MULTIPLY '*'
43 #define EVAL_OPERATOR_DIVIDE '/'
44 #define EVAL_OPERATOR_SIGN_PLUS 'P'
45 #define EVAL_OPERATOR_SIGN_MINUS 'M'
47 // ----------------------------------------------------------------------------
48 // forward function definitions
50 static inline void eval_node_free(EVAL_NODE *op);
51 static inline EVAL_NODE *parse_full_expression(const char **string, int *error);
52 static inline EVAL_NODE *parse_one_full_operand(const char **string, int *error);
53 static inline calculated_number eval_node(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error);
54 static inline void print_parsed_as_node(BUFFER *out, EVAL_NODE *op, int *error);
56 // ----------------------------------------------------------------------------
57 // evaluation of expressions
59 static inline calculated_number eval_check_number(calculated_number n, int *error) {
60 if(unlikely(isnan(n))) {
61 *error = EVAL_ERROR_VALUE_IS_NAN;
65 if(unlikely(isinf(n))) {
66 *error = EVAL_ERROR_VALUE_IS_INFINITE;
73 static inline calculated_number eval_variable(EVAL_EXPRESSION *exp, EVAL_VARIABLE *v, int *error) {
74 // FIXME: do the variable look up here
77 *error = EVAL_ERROR_UNKNOWN_VARIABLE;
78 buffer_sprintf(exp->error_msg, "unknown variable '%s'", v->name);
84 static inline calculated_number eval_value(EVAL_EXPRESSION *exp, EVAL_VALUE *v, int *error) {
88 case EVAL_VALUE_EXPRESSION:
89 n = eval_node(exp, v->expression, error);
92 case EVAL_VALUE_NUMBER:
96 case EVAL_VALUE_VARIABLE:
97 n = eval_variable(exp, v->variable, error);
101 *error = EVAL_ERROR_INVALID_VALUE;
106 return eval_check_number(n, error);
109 calculated_number eval_and(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
110 return eval_value(exp, &op->ops[0], error) && eval_value(exp, &op->ops[1], error);
112 calculated_number eval_or(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
113 return eval_value(exp, &op->ops[0], error) || eval_value(exp, &op->ops[1], error);
115 calculated_number eval_greater_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
116 return eval_value(exp, &op->ops[0], error) >= eval_value(exp, &op->ops[1], error);
118 calculated_number eval_less_than_or_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
119 return eval_value(exp, &op->ops[0], error) <= eval_value(exp, &op->ops[1], error);
121 calculated_number eval_not_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
122 return eval_value(exp, &op->ops[0], error) != eval_value(exp, &op->ops[1], error);
124 calculated_number eval_equal(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
125 return eval_value(exp, &op->ops[0], error) == eval_value(exp, &op->ops[1], error);
127 calculated_number eval_less(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
128 return eval_value(exp, &op->ops[0], error) < eval_value(exp, &op->ops[1], error);
130 calculated_number eval_greater(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
131 return eval_value(exp, &op->ops[0], error) > eval_value(exp, &op->ops[1], error);
133 calculated_number eval_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
134 return eval_value(exp, &op->ops[0], error) + eval_value(exp, &op->ops[1], error);
136 calculated_number eval_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
137 return eval_value(exp, &op->ops[0], error) - eval_value(exp, &op->ops[1], error);
139 calculated_number eval_multiply(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
140 return eval_value(exp, &op->ops[0], error) * eval_value(exp, &op->ops[1], error);
142 calculated_number eval_divide(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
143 return eval_value(exp, &op->ops[0], error) / eval_value(exp, &op->ops[1], error);
145 calculated_number eval_nop(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
146 return eval_value(exp, &op->ops[0], error);
148 calculated_number eval_not(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
149 return !eval_value(exp, &op->ops[0], error);
151 calculated_number eval_sign_plus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
152 return eval_value(exp, &op->ops[0], error);
154 calculated_number eval_sign_minus(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
155 return -eval_value(exp, &op->ops[0], error);
158 static struct operator {
159 const char *print_as;
162 calculated_number (*eval)(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error);
164 // this is a random access array
165 // we always access it with a known EVAL_OPERATOR_X
167 [EVAL_OPERATOR_AND] = { "&&", 2, 2, eval_and },
168 [EVAL_OPERATOR_OR] = { "||", 2, 2, eval_or },
169 [EVAL_OPERATOR_GREATER_THAN_OR_EQUAL] = { ">=", 3, 2, eval_greater_than_or_equal },
170 [EVAL_OPERATOR_LESS_THAN_OR_EQUAL] = { "<=", 3, 2, eval_less_than_or_equal },
171 [EVAL_OPERATOR_NOT_EQUAL] = { "!=", 3, 2, eval_not_equal },
172 [EVAL_OPERATOR_EQUAL] = { "==", 3, 2, eval_equal },
173 [EVAL_OPERATOR_LESS] = { "<", 3, 2, eval_less },
174 [EVAL_OPERATOR_GREATER] = { ">", 3, 2, eval_greater },
175 [EVAL_OPERATOR_PLUS] = { "+", 4, 2, eval_plus },
176 [EVAL_OPERATOR_MINUS] = { "-", 4, 2, eval_minus },
177 [EVAL_OPERATOR_MULTIPLY] = { "*", 5, 2, eval_multiply },
178 [EVAL_OPERATOR_DIVIDE] = { "/", 5, 2, eval_divide },
179 [EVAL_OPERATOR_NOT] = { "!", 6, 1, eval_not },
180 [EVAL_OPERATOR_SIGN_PLUS] = { "+", 6, 1, eval_sign_plus },
181 [EVAL_OPERATOR_SIGN_MINUS] = { "-", 6, 1, eval_sign_minus },
182 [EVAL_OPERATOR_NOP] = { NULL, 7, 1, eval_nop },
183 [EVAL_OPERATOR_EXPRESSION_OPEN] = { NULL, 7, 1, eval_nop },
185 // this should exist in our evaluation list
186 [EVAL_OPERATOR_EXPRESSION_CLOSE] = { NULL, 7, 1, eval_nop }
189 #define eval_precedence(operator) (operators[(unsigned char)(operator)].precedence)
191 static inline calculated_number eval_node(EVAL_EXPRESSION *exp, EVAL_NODE *op, int *error) {
192 if(unlikely(op->count != operators[op->operator].parameters)) {
193 *error = EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS;
197 calculated_number n = operators[op->operator].eval(exp, op, error);
199 return eval_check_number(n, error);
202 // ----------------------------------------------------------------------------
203 // parsed-as generation
205 static inline void print_parsed_as_variable(BUFFER *out, EVAL_VARIABLE *v, int *error) {
207 buffer_sprintf(out, "$%s", v->name);
210 static inline void print_parsed_as_constant(BUFFER *out, calculated_number n) {
212 snprintfz(b, 100, CALCULATED_NUMBER_FORMAT, n);
214 s = &b[strlen(b) - 1];
215 while(s > b && *s == '0') {
220 if(s > b && *s == '.')
223 buffer_strcat(out, b);
226 static inline void print_parsed_as_value(BUFFER *out, EVAL_VALUE *v, int *error) {
228 case EVAL_VALUE_EXPRESSION:
229 print_parsed_as_node(out, v->expression, error);
232 case EVAL_VALUE_NUMBER:
233 print_parsed_as_constant(out, v->number);
236 case EVAL_VALUE_VARIABLE:
237 print_parsed_as_variable(out, v->variable, error);
241 *error = EVAL_ERROR_INVALID_VALUE;
246 static inline void print_parsed_as_node(BUFFER *out, EVAL_NODE *op, int *error) {
247 if(unlikely(op->count != operators[op->operator].parameters)) {
248 *error = EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS;
252 if(operators[op->operator].parameters == 1) {
254 if(operators[op->operator].print_as)
255 buffer_sprintf(out, "%s", operators[op->operator].print_as);
257 //if(op->operator == EVAL_OPERATOR_EXPRESSION_OPEN)
258 // buffer_strcat(out, "(");
260 print_parsed_as_value(out, &op->ops[0], error);
262 //if(op->operator == EVAL_OPERATOR_EXPRESSION_OPEN)
263 // buffer_strcat(out, ")");
266 else if(operators[op->operator].parameters == 2) {
267 buffer_strcat(out, "(");
268 print_parsed_as_value(out, &op->ops[0], error);
270 if(operators[op->operator].print_as)
271 buffer_sprintf(out, " %s ", operators[op->operator].print_as);
273 print_parsed_as_value(out, &op->ops[1], error);
274 buffer_strcat(out, ")");
278 // ----------------------------------------------------------------------------
279 // parsing expressions
282 static inline void skip_spaces(const char **string) {
283 const char *s = *string;
284 while(isspace(*s)) s++;
288 // what character can appear just after an operator keyword
290 static inline int isoperatorterm_word(const char s) {
291 if(isspace(s) || s == '(' || s == '$' || s == '!' || s == '-' || s == '+' || isdigit(s) || !s)
297 // what character can appear just after an operator symbol?
298 static inline int isoperatorterm_symbol(const char s) {
299 if(isoperatorterm_word(s) || isalpha(s))
305 // return 1 if the character should never appear in a variable
306 static inline int isvariableterm(const char s) {
307 if(isalnum(s) || s == '.' || s == '_')
313 // ----------------------------------------------------------------------------
316 static inline int parse_and(const char **string) {
317 const char *s = *string;
320 if((s[0] == 'A' || s[0] == 'a') && (s[1] == 'N' || s[1] == 'n') && (s[2] == 'D' || s[2] == 'd') && isoperatorterm_word(s[3])) {
326 if(s[0] == '&' && s[1] == '&' && isoperatorterm_symbol(s[2])) {
334 static inline int parse_or(const char **string) {
335 const char *s = *string;
338 if((s[0] == 'O' || s[0] == 'o') && (s[1] == 'R' || s[1] == 'r') && isoperatorterm_word(s[2])) {
344 if(s[0] == '|' && s[1] == '|' && isoperatorterm_symbol(s[2])) {
352 static inline int parse_greater_than_or_equal(const char **string) {
353 const char *s = *string;
356 if(s[0] == '>' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
364 static inline int parse_less_than_or_equal(const char **string) {
365 const char *s = *string;
368 if (s[0] == '<' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
376 static inline int parse_greater(const char **string) {
377 const char *s = *string;
380 if(s[0] == '>' && isoperatorterm_symbol(s[1])) {
388 static inline int parse_less(const char **string) {
389 const char *s = *string;
392 if(s[0] == '<' && isoperatorterm_symbol(s[1])) {
400 static inline int parse_equal(const char **string) {
401 const char *s = *string;
404 if(s[0] == '=' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
410 if(s[0] == '=' && isoperatorterm_symbol(s[1])) {
418 static inline int parse_not_equal(const char **string) {
419 const char *s = *string;
422 if(s[0] == '!' && s[1] == '=' && isoperatorterm_symbol(s[2])) {
428 if(s[0] == '<' && s[1] == '>' && isoperatorterm_symbol(s[2])) {
435 static inline int parse_not(const char **string) {
436 const char *s = *string;
439 if((s[0] == 'N' || s[0] == 'n') && (s[1] == 'O' || s[1] == 'o') && (s[2] == 'T' || s[2] == 't') && isoperatorterm_word(s[3])) {
452 static inline int parse_multiply(const char **string) {
453 const char *s = *string;
456 if(s[0] == '*' && isoperatorterm_symbol(s[1])) {
464 static inline int parse_divide(const char **string) {
465 const char *s = *string;
468 if(s[0] == '/' && isoperatorterm_symbol(s[1])) {
476 static inline int parse_minus(const char **string) {
477 const char *s = *string;
480 if(s[0] == '-' && isoperatorterm_symbol(s[1])) {
488 static inline int parse_plus(const char **string) {
489 const char *s = *string;
492 if(s[0] == '+' && isoperatorterm_symbol(s[1])) {
500 static inline int parse_open_subexpression(const char **string) {
501 const char *s = *string;
512 static inline int parse_close_subexpression(const char **string) {
513 const char *s = *string;
524 static inline int parse_variable(const char **string, char *buffer, size_t len) {
525 const char *s = *string;
532 while(*s && !isvariableterm(*s) && i < len)
546 static inline int parse_constant(const char **string, calculated_number *number) {
548 calculated_number n = strtold(*string, &end);
549 if(unlikely(!end || *string == end || isnan(n) || isinf(n))) {
558 static struct operator_parser {
560 int (*parse)(const char **);
561 } operator_parsers[] = {
562 // the order in this list is important!
563 // the first matching will be used
564 // so place the longer of overlapping ones
567 { EVAL_OPERATOR_AND, parse_and },
568 { EVAL_OPERATOR_OR, parse_or },
569 { EVAL_OPERATOR_GREATER_THAN_OR_EQUAL, parse_greater_than_or_equal },
570 { EVAL_OPERATOR_LESS_THAN_OR_EQUAL, parse_less_than_or_equal },
571 { EVAL_OPERATOR_NOT_EQUAL, parse_not_equal },
572 { EVAL_OPERATOR_EQUAL, parse_equal },
573 { EVAL_OPERATOR_LESS, parse_less },
574 { EVAL_OPERATOR_GREATER, parse_greater },
575 { EVAL_OPERATOR_PLUS, parse_plus },
576 { EVAL_OPERATOR_MINUS, parse_minus },
577 { EVAL_OPERATOR_MULTIPLY, parse_multiply },
578 { EVAL_OPERATOR_DIVIDE, parse_divide },
580 /* we should not put in this list the following:
586 * these are handled in code
590 { EVAL_OPERATOR_NOP, NULL }
593 static inline unsigned char parse_operator(const char **string, int *precedence) {
597 for(i = 0 ; operator_parsers[i].parse != NULL ; i++)
598 if(operator_parsers[i].parse(string)) {
599 if(precedence) *precedence = eval_precedence(operator_parsers[i].id);
600 return operator_parsers[i].id;
603 return EVAL_OPERATOR_NOP;
606 // ----------------------------------------------------------------------------
609 static inline EVAL_NODE *eval_node_alloc(int count) {
612 EVAL_NODE *op = callocz(1, sizeof(EVAL_NODE) + (sizeof(EVAL_VALUE) * count));
615 op->operator = EVAL_OPERATOR_NOP;
616 op->precedence = eval_precedence(EVAL_OPERATOR_NOP);
621 static inline void eval_node_set_value_to_node(EVAL_NODE *op, int pos, EVAL_NODE *value) {
623 fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
625 op->ops[pos].type = EVAL_VALUE_EXPRESSION;
626 op->ops[pos].expression = value;
629 static inline void eval_node_set_value_to_constant(EVAL_NODE *op, int pos, calculated_number value) {
631 fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
633 op->ops[pos].type = EVAL_VALUE_NUMBER;
634 op->ops[pos].number = value;
637 static inline void eval_node_set_value_to_variable(EVAL_NODE *op, int pos, const char *variable) {
639 fatal("Invalid request to set position %d of OPERAND that has only %d values", pos + 1, op->count + 1);
641 op->ops[pos].type = EVAL_VALUE_VARIABLE;
642 op->ops[pos].variable = callocz(1, sizeof(EVAL_VARIABLE));
643 op->ops[pos].variable->name = strdupz(variable);
646 static inline void eval_variable_free(EVAL_VARIABLE *v) {
651 static inline void eval_value_free(EVAL_VALUE *v) {
653 case EVAL_VALUE_EXPRESSION:
654 eval_node_free(v->expression);
657 case EVAL_VALUE_VARIABLE:
658 eval_variable_free(v->variable);
666 static inline void eval_node_free(EVAL_NODE *op) {
669 for(i = op->count - 1; i >= 0 ;i--)
670 eval_value_free(&op->ops[i]);
676 // ----------------------------------------------------------------------------
679 // helper function to avoid allocations all over the place
680 static inline EVAL_NODE *parse_next_operand_given_its_operator(const char **string, unsigned char operator_type, int *error) {
681 EVAL_NODE *sub = parse_one_full_operand(string, error);
682 if(!sub) return NULL;
684 EVAL_NODE *op = eval_node_alloc(1);
685 op->operator = operator_type;
686 eval_node_set_value_to_node(op, 0, sub);
690 // parse a full operand, including its sign or other associative operator (e.g. NOT)
691 static inline EVAL_NODE *parse_one_full_operand(const char **string, int *error) {
692 char variable_buffer[EVAL_MAX_VARIABLE_NAME_LENGTH + 1];
693 EVAL_NODE *op1 = NULL;
694 calculated_number number;
696 *error = EVAL_ERROR_OK;
700 *error = EVAL_ERROR_MISSING_OPERAND;
704 if(parse_not(string)) {
705 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_NOT, error);
706 op1->precedence = eval_precedence(EVAL_OPERATOR_NOT);
708 else if(parse_plus(string)) {
709 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_SIGN_PLUS, error);
710 op1->precedence = eval_precedence(EVAL_OPERATOR_SIGN_PLUS);
712 else if(parse_minus(string)) {
713 op1 = parse_next_operand_given_its_operator(string, EVAL_OPERATOR_SIGN_MINUS, error);
714 op1->precedence = eval_precedence(EVAL_OPERATOR_SIGN_MINUS);
716 else if(parse_open_subexpression(string)) {
717 EVAL_NODE *sub = parse_full_expression(string, error);
719 op1 = eval_node_alloc(1);
720 op1->operator = EVAL_OPERATOR_EXPRESSION_OPEN;
721 op1->precedence = eval_precedence(EVAL_OPERATOR_EXPRESSION_OPEN);
722 eval_node_set_value_to_node(op1, 0, sub);
723 if(!parse_close_subexpression(string)) {
724 *error = EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION;
730 else if(parse_variable(string, variable_buffer, EVAL_MAX_VARIABLE_NAME_LENGTH)) {
731 op1 = eval_node_alloc(1);
732 op1->operator = EVAL_OPERATOR_NOP;
733 eval_node_set_value_to_variable(op1, 0, variable_buffer);
735 else if(parse_constant(string, &number)) {
736 op1 = eval_node_alloc(1);
737 op1->operator = EVAL_OPERATOR_NOP;
738 eval_node_set_value_to_constant(op1, 0, number);
741 *error = EVAL_ERROR_UNKNOWN_OPERAND;
743 *error = EVAL_ERROR_MISSING_OPERAND;
748 // parse an operator and the rest of the expression
749 // precedence processing is handled here
750 static inline EVAL_NODE *parse_rest_of_expression(const char **string, int *error, EVAL_NODE *op1) {
751 EVAL_NODE *op2 = NULL;
752 unsigned char operator;
755 operator = parse_operator(string, &precedence);
758 if(operator != EVAL_OPERATOR_NOP) {
759 op2 = parse_one_full_operand(string, error);
761 // error is already reported
766 EVAL_NODE *op = eval_node_alloc(2);
767 op->operator = operator;
768 op->precedence = precedence;
770 eval_node_set_value_to_node(op, 1, op2);
772 // precedence processing
773 // if this operator has a higher precedence compared to its next
774 // put the next operator on top of us (top = evaluated later)
775 // function recursion does the rest...
776 if(op->precedence > op1->precedence && op1->count == 2 && op1->operator != '(' && op1->ops[1].type == EVAL_VALUE_EXPRESSION) {
777 eval_node_set_value_to_node(op, 0, op1->ops[1].expression);
778 op1->ops[1].expression = op;
782 eval_node_set_value_to_node(op, 0, op1);
784 return parse_rest_of_expression(string, error, op);
786 else if(**string == ')') {
790 if(op1) eval_node_free(op1);
792 *error = EVAL_ERROR_MISSING_OPERATOR;
798 // high level function to parse an expression or a sub-expression
799 static inline EVAL_NODE *parse_full_expression(const char **string, int *error) {
800 EVAL_NODE *op1 = NULL;
802 op1 = parse_one_full_operand(string, error);
804 *error = EVAL_ERROR_MISSING_OPERAND;
808 return parse_rest_of_expression(string, error, op1);
811 // ----------------------------------------------------------------------------
814 int expression_evaluate(EVAL_EXPRESSION *exp) {
815 exp->error = EVAL_ERROR_OK;
817 buffer_reset(exp->error_msg);
818 exp->result = eval_node(exp, (EVAL_NODE *)exp->nodes, &exp->error);
820 if(exp->error != EVAL_ERROR_OK) {
821 if(buffer_strlen(exp->error_msg))
822 buffer_strcat(exp->error_msg, "; ");
824 buffer_sprintf(exp->error_msg, "failed to evaluate expression with error %d (%s)", exp->error, expression_strerror(exp->error));
831 EVAL_EXPRESSION *expression_parse(const char *string, const char **failed_at, int *error) {
832 const char *s = string;
833 int err = EVAL_ERROR_OK;
834 unsigned long pos = 0;
836 EVAL_NODE *op = parse_full_expression(&s, &err);
843 err = EVAL_ERROR_REMAINING_GARBAGE;
846 if (failed_at) *failed_at = s;
847 if (error) *error = err;
850 pos = s - string + 1;
851 error("failed to parse expression '%s': %s at character %lu (i.e.: '%s').", string, expression_strerror(err), pos, s);
855 BUFFER *out = buffer_create(1024);
856 print_parsed_as_node(out, op, &err);
857 if(err != EVAL_ERROR_OK) {
858 error("failed to re-generate expression '%s' with reason: %s", string, expression_strerror(err));
864 EVAL_EXPRESSION *exp = callocz(1, sizeof(EVAL_EXPRESSION));
866 exp->source = strdupz(string);
867 exp->parsed_as = strdupz(buffer_tostring(out));
870 exp->error_msg = buffer_create(100);
871 exp->nodes = (void *)op;
876 void expression_free(EVAL_EXPRESSION *exp) {
879 if(exp->nodes) eval_node_free((EVAL_NODE *)exp->nodes);
880 freez((void *)exp->source);
881 freez((void *)exp->parsed_as);
882 buffer_free(exp->error_msg);
886 const char *expression_strerror(int error) {
891 case EVAL_ERROR_MISSING_CLOSE_SUBEXPRESSION:
892 return "missing closing parenthesis";
894 case EVAL_ERROR_UNKNOWN_OPERAND:
895 return "unknown operand";
897 case EVAL_ERROR_MISSING_OPERAND:
898 return "expected operand";
900 case EVAL_ERROR_MISSING_OPERATOR:
901 return "expected operator";
903 case EVAL_ERROR_REMAINING_GARBAGE:
904 return "remaining characters after expression";
906 case EVAL_ERROR_INVALID_VALUE:
907 return "invalid value structure - internal error";
909 case EVAL_ERROR_INVALID_NUMBER_OF_OPERANDS:
910 return "wrong number of operands for operation - internal error";
912 case EVAL_ERROR_VALUE_IS_NAN:
913 return "value or variable is missing or is not a number";
915 case EVAL_ERROR_VALUE_IS_INFINITE:
916 return "computed value is infinite";
918 case EVAL_ERROR_UNKNOWN_VARIABLE:
919 return "undefined variable";
922 return "unknown error";