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view lwlink/expr.h @ 169:99300be2d3bd
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author | lost |
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date | Sun, 08 Feb 2009 03:00:44 +0000 |
parents | 106c2fe3c9d9 |
children | 299c5d793aca |
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/* expr.h Copyright © 2009 William Astle This file is part of LWLINK. LWLINK is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* Definitions for expression evaluator */ #ifndef __expr_h_seen__ #define __expr_h_seen__ #ifndef __expr_c_seen__ #define __expr_E__ extern #else #define __expr_E__ #endif // term types #define LW_TERM_NONE 0 #define LW_TERM_OPER 1 // an operator #define LW_TERM_INT 2 // 32 bit signed integer #define LW_TERM_SYM 3 // symbol reference // operator types #define LW_OPER_NONE 0 #define LW_OPER_PLUS 1 // + #define LW_OPER_MINUS 2 // - #define LW_OPER_TIMES 3 // * #define LW_OPER_DIVIDE 4 // / #define LW_OPER_MOD 5 // % #define LW_OPER_INTDIV 6 // \ (don't end line with \) #define LW_OPER_BWAND 7 // bitwise AND #define LW_OPER_BWOR 8 // bitwise OR #define LW_OPER_BWXOR 9 // bitwise XOR #define LW_OPER_AND 10 // boolean AND #define LW_OPER_OR 11 // boolean OR #define LW_OPER_NEG 12 // - unary negation (2's complement) #define LW_OPER_COM 13 // ^ unary 1's complement // term structure typedef struct lw_expr_term_s { int term_type; // type of term (see above) char *symbol; // name of a symbol int value; // value of the term (int) or operator number (OPER) } lw_expr_term_t; // type for an expression evaluation stack typedef struct lw_expr_stack_node_s lw_expr_stack_node_t; struct lw_expr_stack_node_s { lw_expr_term_t *term; lw_expr_stack_node_t *prev; lw_expr_stack_node_t *next; }; typedef struct lw_expr_stack_s { lw_expr_stack_node_t *head; lw_expr_stack_node_t *tail; } lw_expr_stack_t; __expr_E__ void lw_expr_term_free(lw_expr_term_t *t); __expr_E__ lw_expr_term_t *lw_expr_term_create_oper(int oper); __expr_E__ lw_expr_term_t *lw_expr_term_create_sym(char *sym, int symtype); __expr_E__ lw_expr_term_t *lw_expr_term_create_int(int val); __expr_E__ lw_expr_term_t *lw_expr_term_dup(lw_expr_term_t *t); __expr_E__ void lw_expr_stack_free(lw_expr_stack_t *s); __expr_E__ lw_expr_stack_t *lw_expr_stack_create(void); __expr_E__ void lw_expr_stack_push(lw_expr_stack_t *s, lw_expr_term_t *t); __expr_E__ lw_expr_term_t *lw_expr_stack_pop(lw_expr_stack_t *s); // simplify expression __expr_E__ int lw_expr_reval(lw_expr_stack_t *s, lw_expr_stack_t *(*sfunc)(char *sym, int symtype, void *state), void *state); // useful macros // is the expression "simple" (one term)? #define lw_expr_is_simple(s) ((s) -> head == (s) -> tail) // is the expression constant? #define lw_expr_is_constant(s) (lw_expr_is_simple(s) && (!((s) -> head) || (s) -> head -> term -> term_type == LW_TERM_INT)) // get the constant value of an expression or 0 if not constant #define lw_expr_get_value(s) (lw_expr_is_constant(s) ? ((s) -> head ? (s) -> head -> term -> value : 0) : 0) #undef __expr_E__ #endif // __expr_h_seen__