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comparison src/expr.c @ 76:2fe5fd7d65a3

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Checkpointing object target implementation
author lost
date Thu, 08 Jan 2009 02:57:24 +0000
parents 73423b66e511
children 718998b673ee
comparison
equal deleted inserted replaced
75:92eb93bffa28 76:2fe5fd7d65a3
652 652
653 Returns NULL on a parse error or otherwise invalid expression. *outp will 653 Returns NULL on a parse error or otherwise invalid expression. *outp will
654 contain the pointer to the next character after the expression if and only 654 contain the pointer to the next character after the expression if and only
655 if there is no error. In the case of an error, *outp is undefined. 655 if there is no error. In the case of an error, *outp is undefined.
656 */ 656 */
657 lwasm_expr_stack_t *lwasm_expr_eval(const char *inp, const char **outp, int (*sfunc)(char *sym, void *state, int *val), void *state) 657 lwasm_expr_stack_t *lwasm_expr_eval(const char *inp, const char **outp, lwasm_expr_stack_t *(*sfunc)(char *sym, void *state), void *state)
658 { 658 {
659 lwasm_expr_stack_t *s; 659 lwasm_expr_stack_t *s;
660 const char *p; 660 const char *p;
661 int rval; 661 int rval;
662 662
701 701
702 repeat the scan until no futher simplications are found or if there are no 702 repeat the scan until no futher simplications are found or if there are no
703 further operators or only a single term remains 703 further operators or only a single term remains
704 704
705 */ 705 */
706 int lwasm_expr_reval(lwasm_expr_stack_t *s, int (*sfunc)(char *sym, void *state, int *val), void *state) 706 int lwasm_expr_reval(lwasm_expr_stack_t *s, lwasm_expr_stack_t *(*sfunc)(char *sym, void *state), void *state)
707 { 707 {
708 lwasm_expr_stack_node_t *n; 708 lwasm_expr_stack_node_t *n, *n2;
709 int sval; 709 lwasm_expr_stack_t *ss;
710 710 int c;
711
712 next_iter_sym:
711 // resolve symbols 713 // resolve symbols
712 // symbols that do not resolve to a constant are left alone 714 // symbols that do not resolve to an expression are left alone
713 for (n = s -> head; n; n = n -> next) 715 for (c = 0, n = s -> head; n; n = n -> next)
714 { 716 {
715 if (n -> term -> term_type == LWASM_TERM_SYM) 717 if (n -> term -> term_type == LWASM_TERM_SYM)
716 { 718 {
717 if (sfunc(n -> term -> symbol, state, &sval) == 0) 719 ss = sfunc(n -> term -> symbol, state);
720 if (ss)
718 { 721 {
719 n -> term -> term_type = LWASM_TERM_INT; 722 c++;
720 n -> term -> value = sval; 723 // splice in the result stack
721 lwasm_free(n -> term -> symbol); 724 if (n -> prev)
722 n -> term -> symbol = NULL; 725 {
726 n -> prev -> next = ss -> head;
727 }
728 else
729 {
730 s -> head = ss -> head;
731 }
732 ss -> head -> prev = n -> prev;
733 ss -> tail -> next = n -> next;
734 if (n -> next)
735 {
736 n -> next -> prev = ss -> tail;
737 }
738 else
739 {
740 s -> tail = ss -> tail;
741 }
742 lwasm_expr_term_free(n -> term);
743 lwasm_free(n);
744 n = ss -> tail;
745
746 ss -> head = NULL;
747 ss -> tail = NULL;
748 lwasm_expr_stack_free(ss);
723 } 749 }
724 } 750 }
725 } 751 }
752 if (c)
753 goto next_iter_sym;
726 754
727 next_iter: 755 next_iter:
728 // a single term 756 // a single term
729 if (s -> head == s -> tail) 757 if (s -> head == s -> tail)
730 return 0; 758 return 0;