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First pass at expression evaluator complete
author lost
date Thu, 01 Jan 2009 23:55:18 +0000
parents df0c4a46af8f
children ec0bf61a5502
comparison
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17:df0c4a46af8f 18:218aabbc3b1a
42 #define LWASM_OPER_PLUS 1 // + 42 #define LWASM_OPER_PLUS 1 // +
43 #define LWASM_OPER_MINUS 2 // - 43 #define LWASM_OPER_MINUS 2 // -
44 #define LWASM_OPER_TIMES 3 // * 44 #define LWASM_OPER_TIMES 3 // *
45 #define LWASM_OPER_DIVIDE 4 // / 45 #define LWASM_OPER_DIVIDE 4 // /
46 #define LWASM_OPER_MOD 5 // % 46 #define LWASM_OPER_MOD 5 // %
47 #define LWASM_OPER_INTDIV 6 // \ 47 #define LWASM_OPER_INTDIV 6 // \ (don't end line with \)
48 #define LWASM_OPER_BWAND 7 // bitwise AND 48 #define LWASM_OPER_BWAND 7 // bitwise AND
49 #define LWASM_OPER_BWOR 8 // bitwise OR 49 #define LWASM_OPER_BWOR 8 // bitwise OR
50 #define LWASM_OPER_BWXOR 9 // bitwise XOR 50 #define LWASM_OPER_BWXOR 9 // bitwise XOR
51 #define LWASM_OPER_AND 10 // boolean AND 51 #define LWASM_OPER_AND 10 // boolean AND
52 #define LWASM_OPER_OR 11 // boolean OR 52 #define LWASM_OPER_OR 11 // boolean OR
87 __expr_E__ lwasm_expr_stack_t *lwasm_expr_stack_create(void); 87 __expr_E__ lwasm_expr_stack_t *lwasm_expr_stack_create(void);
88 88
89 __expr_E__ void lwasm_expr_stack_push(lwasm_expr_stack_t *s, lwasm_expr_term_t *t); 89 __expr_E__ void lwasm_expr_stack_push(lwasm_expr_stack_t *s, lwasm_expr_term_t *t);
90 __expr_E__ lwasm_expr_term_t *lwasm_expr_stack_pop(lwasm_expr_stack_t *s); 90 __expr_E__ lwasm_expr_term_t *lwasm_expr_stack_pop(lwasm_expr_stack_t *s);
91 91
92 /*
93 Evaluate an expression. The result is an lwasm_expr_stack_t pointer. If the
94 expression evaluates to a constant result, the stack will contain exactly one
95 value which will be a constant. Otherwise, the stack will contain the
96 expression with all operations that can be evaluated completely evaluated.
97 You must call lwasm_expr_stack_free() on the result when you are finished
98 with it.
99 */
100 __expr_E__ lwasm_expr_stack_t *lwasm_expr_eval(const char *inp, const char **outp);
101
102 // simplify expression
103 __expr_E__ int lwasm_expr_reval(lwasm_expr_stack_t *s);
104
105 // useful macros
106 // is the expression "simple" (one term)?
107 #define lwasm_expr_is_simple(s) ((s) -> head == (s) -> tail)
108
109 // is the expression constant?
110 #define lwasm_expr_is_constant(s) (lwasm_expr_is_simple(s) && (s) -> head -> term -> term_type == LWASM_TERM_INT)
111
112 // get the constant value of an expression or 0 if not constant
113 #define lwasm_expr_get_value(s) (lwasm_expr_is_constant(s) ? (s) -> head -> term -> value : 0)
114
92 #undef __expr_E__ 115 #undef __expr_E__
93 116
94 #endif // __expr_h_seen__ 117 #endif // __expr_h_seen__