static LIST st_TraverseTreeGenPreTest(CONTEXT IndexContext, st_INDEX StIndex, st_MINMAX MinMax) /************************************************************** INPUT: RETURNS: EFFECTS: ***************************************************************/ { int Save; LIST Result, CurrentList; st_INDEX CurrentNode; /* PREPARE TRAVERSAL */ Save = stack_Bottom(); Result = list_Nil(); CurrentList = StIndex->subnodes; cont_StartBinding(); for (;;) { /* BACKTRACK A BIG STEP */ if (list_Empty(CurrentList)) { cont_StopAndBackTrack(); if (stack_Empty(Save)) return Result; CurrentList = stack_PopResult(); } /* DESCENDING */ for (CurrentNode = (st_INDEX)list_Car(CurrentList); (MinMax >= st_Min(CurrentNode)) && subst_Match(IndexContext, CurrentNode->subst); CurrentList = CurrentNode->subnodes, CurrentNode = (st_INDEX)list_Car(CurrentList)) if (st_IsLeaf(CurrentNode)) { Result = list_Append(CurrentNode->entries, Result); break; } else if (list_Cdr(CurrentList)) { stack_Push(list_Cdr(CurrentList)); cont_StartBinding(); } else cont_StopAndStartBinding(); /* BACKTRACK LEAF OR INNER NODE */ CurrentList = list_Cdr(CurrentList); cont_BackTrackAndStart(); } }
static int kbo_CompVarCondAndWeight(TERM Term1, BOOL *VarCond1, TERM Term2, BOOL *VarCond2) /************************************************************** INPUT: Two terms and two pointers to booleans. EFFECT: Sets the booleans with respect to the kbo variable condition. Computes the kbo weight difference. ***************************************************************/ { SYMBOL MaxVar1,MaxVar2; TERM Term; LIST Scan; int i,Stack,Weight; *VarCond1 = *VarCond2 = TRUE; MaxVar1 = term_MaxVar(Term1); MaxVar2 = term_MaxVar(Term2); Stack = stack_Bottom(); Weight = 0; if (MaxVar1 < MaxVar2) MaxVar1 = MaxVar2; for (i = 0; i <= MaxVar1; i++) { ord_VARCOUNT[i][0] = 0; ord_VARCOUNT[i][1] = 0; } Term = Term1; if (term_IsStandardVariable(Term)) { ord_VARCOUNT[term_TopSymbol(Term)][0]++; Weight += kbo_MINWEIGHT; } else { Weight += symbol_Weight(term_TopSymbol(Term)); if (term_IsComplex(Term)) stack_Push(term_ArgumentList(Term)); } while (!stack_Empty(Stack)) { Scan = stack_Top(); Term = (TERM)list_Car(Scan); stack_RplacTop(list_Cdr(Scan)); if (term_IsStandardVariable(Term)) { Weight += kbo_MINWEIGHT; ord_VARCOUNT[term_TopSymbol(Term)][0]++; } else { Weight += symbol_Weight(term_TopSymbol(Term)); if (term_IsComplex(Term)) stack_Push(term_ArgumentList(Term)); } while (!stack_Empty(Stack) && list_Empty(stack_Top())) stack_Pop(); } Term = Term2; if (term_IsStandardVariable(Term)) { Weight -= kbo_MINWEIGHT; ord_VARCOUNT[term_TopSymbol(Term)][1]++; } else { Weight -= symbol_Weight(term_TopSymbol(Term)); if (term_IsComplex(Term)) stack_Push(term_ArgumentList(Term)); } while (!stack_Empty(Stack)) { Scan = stack_Top(); Term = (TERM)list_Car(Scan); stack_RplacTop(list_Cdr(Scan)); if (term_IsStandardVariable(Term)) { Weight -= kbo_MINWEIGHT; ord_VARCOUNT[term_TopSymbol(Term)][1]++; } else { Weight -= symbol_Weight(term_TopSymbol(Term)); if (term_IsComplex(Term)) stack_Push(term_ArgumentList(Term)); } while (!stack_Empty(Stack) && list_Empty(stack_Top())) stack_Pop(); } for (i = 0; i <= MaxVar1; i++) { if (ord_VARCOUNT[i][0] < ord_VARCOUNT[i][1]) { *VarCond1 = FALSE; if (!*VarCond2) return Weight; } if (ord_VARCOUNT[i][0] > ord_VARCOUNT[i][1]) { *VarCond2 = FALSE; if (!*VarCond1) return Weight; } } return Weight; }