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rules-sort.c
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/**************************************************************/
/* ********************************************************** */
/* * * */
/* * INFERENCE RULES FOR SORTS * */
/* * * */
/* * $Module: SORTRULES * */
/* * * */
/* * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001 * */
/* * MPI fuer Informatik * */
/* * * */
/* * This program 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 2 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, write * */
/* * to the Free Software Foundation, Inc., 59 Temple * */
/* * Place, Suite 330, Boston, MA 02111-1307 USA * */
/* * * */
/* * * */
/* $Revision$ * */
/* $State$ * */
/* $Date$ * */
/* $Author$ * */
/* * * */
/* * Contact: * */
/* * Christoph Weidenbach * */
/* * MPI fuer Informatik * */
/* * Stuhlsatzenhausweg 85 * */
/* * 66123 Saarbruecken * */
/* * Email: weidenb@mpi-sb.mpg.de * */
/* * Germany * */
/* * * */
/* ********************************************************** */
/**************************************************************/
/* $RCSfile$ */
/**************************************************************/
/* Includes */
/**************************************************************/
#include "rules-sort.h"
/**************************************************************/
/* Functions */
/**************************************************************/
static LIST inf_GetForwardPartnerLits(LITERAL, st_INDEX);
static SORT inf_GetSortFromLits(LIST, SORTTHEORY);
static BOOL inf_SubsortPrecheck(CLAUSE Clause, LIST TLits, LITERAL Special,
st_INDEX Index, SORTTHEORY SortTheory)
/**************************************************************
INPUT: A clause, a list of constraint literal indices in
that clause, a special literal, an index of clauses,
and the actual sort theory.
RETURNS: TRUE, if there exists any subsort of the <TLits> sort.
***************************************************************/
{
SORT tSort, unifierSort;
LIST unifiers;
BOOL result;
unifiers = inf_GetForwardPartnerLits(clause_GetLiteral(Clause,(int)list_Car(TLits)),
Index);
unifierSort = inf_GetSortFromLits(unifiers, SortTheory);
list_Delete(unifiers);
tSort = sort_TopSort();
for (; !list_Empty(TLits); TLits = list_Cdr(TLits)) {
TERM actAtom = clause_GetLiteralAtom(Clause, (int)list_Car(TLits));
tSort = sort_Intersect(sort_TheorySortOfSymbol(SortTheory, term_TopSymbol(actAtom)),
tSort);
}
tSort = list_PointerDeleteDuplicates(tSort);
if (Special == NULL)
result = sort_TheoryIsSubsortOf(SortTheory, unifierSort, tSort);
else {
SORT extraSort;
extraSort = sort_TheorySortOfSymbol(SortTheory, clause_LiteralPredicate(Special));
result = sort_TheoryIsSubsortOfExtra(SortTheory, extraSort, unifierSort, tSort);
sort_Delete(extraSort);
}
sort_Delete(tSort);
sort_Delete(unifierSort);
return result;
}
static LIST inf_GetSortResolutionPartnerLits(TERM Atom, st_INDEX Index)
/**************************************************************
INPUT: A clause, and an Index of clauses.
RETURNS: A list of literals with which sortresolution is possible.
MEMORY: Allocates memory for the list.
***************************************************************/
{
LIST Result, TermList, LitScan;
LITERAL NextLit;
CLAUSE Clause;
#ifdef CHECK
if (!term_IsAtom(Atom)) {
misc_StartErrorReport();
misc_ErrorReport("\n In inf_GetSortResolutionPartnerLits: Variable as atom input.\n");
misc_FinishErrorReport();
}
#endif
Result = list_Nil();
TermList = st_GetUnifier(cont_LeftContext(), Index, cont_RightContext(), Atom);
for ( ; !list_Empty(TermList); TermList = list_Pop(TermList)) {
if (term_IsAtom(list_Car(TermList))) {
for (LitScan = sharing_NAtomDataList(list_Car(TermList));
!list_Empty(LitScan);
LitScan = list_Cdr(LitScan)){
NextLit = list_Car(LitScan);
Clause = clause_LiteralOwningClause(NextLit);
if (clause_LiteralIsPositive(NextLit) &&
clause_LiteralGetFlag(NextLit,STRICTMAXIMAL) &&
clause_GetFlag(Clause, WORKEDOFF) &&
clause_HasSolvedConstraint(Clause) &&
!list_PointerMember(Result, NextLit))
Result = list_Cons(NextLit, Result);
}
}
}
return Result;
}
static CLAUSE inf_BuildConstraintHyperResolvent(CLAUSE Clause, LIST Lits,
SUBST Subst, LIST Foundlits,
FLAGSTORE Flags,
PRECEDENCE Precedence)
/**************************************************************
INPUT: A <Clause> where the sort constraint is resolved,
a list <Lits> of constraint indices in <Clause> where
all corresponding constraints have the same term,
the overall substitution <Subst>,
a list <Foundlits> of literals of found partner clauses,
a flag store and a precedence.
RETURNS: A clause, the resolvent of a resolution step.
***************************************************************/
{
CLAUSE NewClause, ClauseCopy;
LIST Constraint, Antecedent, Succedent, ParentCls, ParentLits, Scan;
TERM Atom;
SYMBOL MaxVar,MaxCand;
int i,bound, depth;
BOOL IsFromEmptySort;
LIST Partners;
ParentCls = list_Nil();
ParentLits = list_Nil();
Constraint = list_Nil();
Antecedent = list_Nil();
Succedent = list_Nil();
Partners = list_Nil();
depth = clause_Depth(Clause);
for (Scan=Foundlits; !list_Empty(Scan); Scan=list_Cdr(Scan))
depth = misc_Max(depth,
clause_Depth(clause_LiteralOwningClause(list_Car(Scan))));
ClauseCopy = clause_Copy(Clause);
Partners = list_Cons(ClauseCopy, Partners);
clause_SubstApply(Subst, ClauseCopy);
IsFromEmptySort = term_IsVariable(term_FirstArgument(
clause_GetLiteralAtom(Clause, (int)list_Car(Lits))));
bound = clause_LastConstraintLitIndex(ClauseCopy);
for (i = clause_FirstLitIndex(); i <= bound; i++)
if (!list_PointerMember(Lits, (POINTER)i)) {
Atom = term_Copy(clause_GetLiteralAtom(ClauseCopy, i));
Constraint = list_Cons(Atom, Constraint);
}
else {
ParentCls = list_Cons((POINTER)clause_Number(ClauseCopy), ParentCls);
ParentLits = list_Cons((POINTER)i, ParentLits);
}
bound = clause_LastAntecedentLitIndex(ClauseCopy);
for ( ; i <= bound; i++) {
Atom = term_Copy(clause_GetLiteralAtom(ClauseCopy, i));
Antecedent = list_Cons(Atom, Antecedent);
}
bound = clause_LastSuccedentLitIndex(ClauseCopy);
for (; i <= bound; i++) {
Atom = term_Copy(clause_GetLiteralAtom(ClauseCopy, i));
Succedent = list_Cons(Atom, Succedent);
}
bound = clause_LastConstraintLitIndex(Clause);
for (i = clause_FirstLitIndex(); i <= bound; i++) {
/* Hier sollen die gematchten Constraintliterale dazu fuehren, dass die */
/* c,a und s- literale der Partnerclauses in die Listen kommen... */
if (list_PointerMember(Lits, (POINTER)i)) {
CLAUSE PartnerCopy;
LITERAL PLit;
TERM PAtom;
SUBST NewSubst,RightSubst;
int j,lc,la,n,PLitInd;
Atom = clause_GetLiteralAtom(ClauseCopy, i);
NewClause = clause_CreateUnnormalized(Constraint, Antecedent, Succedent);
list_Delete(Constraint);
list_Delete(Antecedent);
list_Delete(Succedent);
Constraint = list_Nil();
Antecedent = list_Nil();
Succedent = list_Nil();
/* Find corresponding Foundlit: */
for (Scan = Foundlits;
term_TopSymbol(Atom) !=
term_TopSymbol(clause_LiteralAtom(list_Car(Scan)));
Scan = list_Cdr(Scan));
PLit = list_Car(Scan);
PLitInd = clause_LiteralGetIndex(PLit);
PartnerCopy = clause_Copy(clause_LiteralOwningClause(PLit));
Partners = list_Cons(PartnerCopy, Partners);
ParentCls = list_Cons((POINTER)clause_Number(PartnerCopy), ParentCls);
ParentLits = list_Cons((POINTER)PLitInd, ParentLits);
MaxVar = clause_SearchMaxVar(ClauseCopy);
MaxCand = clause_SearchMaxVar(NewClause);
MaxVar = ((MaxVar > MaxCand) ? MaxVar : MaxCand);
/* MaxVar is the maximal variable in the new clause or the ClauseCopy, */
/* the latter to guarantee the stability of variable names. */
clause_RenameVarsBiggerThan(PartnerCopy, MaxVar);
PLit = clause_GetLiteral(PartnerCopy, PLitInd);
PAtom = clause_LiteralAtom(PLit);
cont_Check();
if (!unify_UnifyNoOC(cont_LeftContext(), PAtom, cont_RightContext(), Atom)) {
misc_StartErrorReport();
misc_ErrorReport("\n In inf_BuildConstraintHyperResolvent: Unification failed.");
misc_FinishErrorReport();
}
subst_ExtractUnifier(cont_LeftContext(), &RightSubst, cont_RightContext(), &NewSubst);
cont_Reset();
clause_SubstApply(NewSubst, NewClause);
clause_SubstApply(NewSubst, ClauseCopy);
subst_Delete(NewSubst);
n = clause_Length(PartnerCopy);
lc = clause_LastConstraintLitIndex(PartnerCopy);
la = clause_LastAntecedentLitIndex(PartnerCopy);
for (j = clause_FirstLitIndex(); j < n; j++) {
if (j <= lc)
Constraint = list_Cons(subst_Apply(RightSubst,
term_Copy(clause_GetLiteralAtom(PartnerCopy, j))),
Constraint);
else if (j <= la)
Antecedent = list_Cons(subst_Apply(RightSubst,
term_Copy(clause_GetLiteralAtom(PartnerCopy, j))),
Antecedent);
else if (j != PLitInd)
Succedent = list_Cons(subst_Apply(RightSubst,
term_Copy(clause_GetLiteralAtom(PartnerCopy, j))),
Succedent);
}
subst_Delete(RightSubst);
n = clause_Length(NewClause);
lc = clause_LastConstraintLitIndex(NewClause);
la = clause_LastAntecedentLitIndex(NewClause);
for (j = clause_FirstLitIndex(); j < n; j++) {
if (j <= lc)
Constraint = list_Cons(term_Copy(clause_GetLiteralAtom(NewClause, j)),
Constraint);
else if (j <= la)
Antecedent = list_Cons(term_Copy(clause_GetLiteralAtom(NewClause, j)),
Antecedent);
else
Succedent = list_Cons(term_Copy(clause_GetLiteralAtom(NewClause, j)),
Succedent);
}
clause_Delete(NewClause);
clause_DecreaseCounter();
}
}
NewClause = clause_Create(Constraint, Antecedent, Succedent, Flags,Precedence);
list_Delete(Constraint);
list_Delete(Antecedent);
list_Delete(Succedent);
if (IsFromEmptySort)
clause_SetFromEmptySort(NewClause);
else
clause_SetFromSortResolution(NewClause);
clause_SetDepth(NewClause, depth + 1);
clause_SetSplitDataFromList(NewClause, Partners);
clause_DeleteClauseList(Partners);
clause_SetParentClauses(NewClause, list_NReverse(ParentCls));
clause_SetParentLiterals(NewClause, list_NReverse(ParentLits));
return NewClause;
}
static LIST inf_ConstraintHyperResolvents(CLAUSE Clause, LIST Lits,
SUBST Subst, LIST Restlits,
LIST Foundlits, st_INDEX Index,
FLAGSTORE Flags, PRECEDENCE Precedence)
/**************************************************************
INPUT: A <Clause> where the sort constraint is resolved,
a list <Lits> of constraint indices in <Clause> where
all corresponding constraints have the same term,
the overall substitution <Subst>,
a list <Restlits> of constraint indeces for which
a partner clause is searched with respect to <Index>,
a list <Foundlits> of literals of already found partner clauses,
a flag store and a precedence.
RETURNS: The list of possible resolvents.
***************************************************************/
{
if (list_Empty(Restlits))
return list_List(inf_BuildConstraintHyperResolvent(Clause,Lits,Subst,
Foundlits, Flags,
Precedence));
else {
CLAUSE PartnerCopy;
LITERAL Lit, PLit;
LIST Result, NextLits;
TERM AtomCopy;
SUBST NewSubst, RightSubst, HelpSubst;
SYMBOL MaxVar, MaxCand;
int PLitInd;
Result = list_Nil();
Lit = clause_GetLiteral(Clause, (int) list_Car(Restlits));
AtomCopy = subst_Apply(Subst, term_Copy(clause_LiteralAtom(Lit)));
NextLits = inf_GetSortResolutionPartnerLits(AtomCopy,Index);
MaxVar = clause_MaxVar(Clause);
MaxCand = clause_AtomMaxVar(AtomCopy);
MaxVar = (symbol_GreaterVariable(MaxVar, MaxCand) ? MaxVar : MaxCand);
for ( ; !list_Empty(NextLits); NextLits = list_Pop(NextLits)) {
PLit = list_Car(NextLits);
PLitInd = clause_LiteralGetIndex(PLit);
Foundlits = list_Cons(PLit, Foundlits);
PartnerCopy = clause_Copy(clause_LiteralOwningClause(PLit));
clause_RenameVarsBiggerThan(PartnerCopy, MaxVar);
PLit = clause_GetLiteral(PartnerCopy, PLitInd);
cont_Check();
unify_UnifyNoOC(cont_LeftContext(), AtomCopy,
cont_RightContext(), clause_LiteralAtom(PLit));
subst_ExtractUnifier(cont_LeftContext(), &NewSubst, cont_RightContext(), &RightSubst);
cont_Reset();
subst_Delete(RightSubst);
HelpSubst = NewSubst;
NewSubst = subst_Compose(NewSubst, subst_Copy(Subst));
Result = list_Nconc(inf_ConstraintHyperResolvents(Clause, Lits, NewSubst,
list_Cdr(Restlits),
Foundlits, Index, Flags,
Precedence),
Result);
subst_Delete(NewSubst);
subst_Delete(HelpSubst);
clause_Delete(PartnerCopy);
Foundlits = list_Pop(Foundlits);
}
term_Delete(AtomCopy);
return Result;
}
}
LIST inf_BackwardSortResolution(CLAUSE GivenClause, st_INDEX Index,
SORTTHEORY SortTheory, BOOL Precheck,
FLAGSTORE Flags, PRECEDENCE Precedence)
/**************************************************************
INPUT: A clause with a solved sort constraint, an index of clauses,
a sort theory, a boolean flag indicating whether the subsort
precheck can be applied, a flag store and a precedence.
RETURNS: A list of clauses inferred from the GivenClause by
SortResolution with the given clause.
MEMORY: A list of clauses is produced, where memory for the list
and the clauses is allocated.
***************************************************************/
{
LIST result;
int i, ls;
#ifdef CHECK
if (!clause_IsClause(GivenClause, Flags, Precedence) ||
!clause_HasSolvedConstraint(GivenClause)) {
misc_StartErrorReport();
misc_ErrorReport("\n In inf_BackwardSortResolution: Illegal input.\n");
misc_FinishErrorReport();
}
#endif
result = list_Nil();
ls = clause_LastSuccedentLitIndex(GivenClause);
for (i = clause_FirstSuccedentLitIndex(GivenClause); i <= ls; i++) {
LITERAL pLit;
TERM pAtom;
pLit = clause_GetLiteral(GivenClause, i);
pAtom = clause_LiteralAtom(pLit);
if (clause_LiteralGetFlag(pLit,STRICTMAXIMAL) &&
clause_LiteralIsSort(pLit)) {
LIST termList;
termList = st_GetUnifier(cont_LeftContext(),Index,cont_RightContext(),pAtom);
for ( ; !list_Empty(termList); termList = list_Pop(termList)){
if (term_IsAtom(list_Car(termList)) &&
!term_IsVariable(term_FirstArgument(list_Car(termList)))) {
LIST litScan;
litScan = sharing_NAtomDataList(list_Car(termList));
for ( ; !list_Empty(litScan); litScan = list_Cdr(litScan)) {
LITERAL gLit;
CLAUSE gClause;
gLit = list_Car(litScan);
gClause = clause_LiteralOwningClause(gLit);
if (clause_LiteralGetIndex(gLit) < clause_FirstAntecedentLitIndex(gClause) &&
clause_GetFlag(gClause,WORKEDOFF)) {
TERM gAtom;
int lc, gi, j;
LIST tLits, restLits;
gAtom = clause_LiteralAtom(gLit);
lc = clause_LastConstraintLitIndex(gClause);
gi = clause_LiteralGetIndex(gLit);
tLits = list_List((POINTER)gi);
restLits = list_Nil();
for (j = clause_FirstLitIndex(); j <= lc; j++) {
LITERAL tCand;
tCand = clause_GetLiteral(gClause, j);
if (j != gi &&
term_FirstArgument(clause_LiteralAtom(tCand))
== term_FirstArgument(gAtom)) {
tLits = list_Cons((POINTER)j, tLits);
restLits = list_Cons((POINTER)j, restLits);
}
}
if (!Precheck ||
inf_SubsortPrecheck(gClause,tLits,pLit,Index,SortTheory)) {
CLAUSE pClauseCopy;
SYMBOL minVar;
LIST foundLits;
SUBST leftSubst, rightSubst;
pClauseCopy = clause_Copy(GivenClause);
minVar = clause_MaxVar(gClause);
foundLits = list_List(pLit);
clause_RenameVarsBiggerThan(pClauseCopy, minVar);
pAtom = clause_GetLiteralAtom(pClauseCopy, i);
/* set, to unify correctly! */
cont_Check();
unify_UnifyNoOC(cont_LeftContext(), gAtom, cont_RightContext(), pAtom);
subst_ExtractUnifier(cont_LeftContext(), &leftSubst,
cont_RightContext(), &rightSubst);
cont_Reset();
subst_Delete(rightSubst);
result =
list_Nconc(inf_ConstraintHyperResolvents(gClause, tLits,
leftSubst, restLits,
foundLits, Index,
Flags, Precedence),
result);
pAtom = clause_LiteralAtom(pLit);
subst_Delete(leftSubst);
list_Delete(foundLits);
clause_Delete(pClauseCopy);
} /* if Precheck */
list_Delete(tLits);
list_Delete(restLits);
}
}
}
}
}
}
return result;
}
LIST inf_ForwardSortResolution(CLAUSE GivenClause, st_INDEX Index,
SORTTHEORY SortTheory, BOOL Precheck,
FLAGSTORE Flags, PRECEDENCE Precedence)
/**************************************************************
INPUT: A clause with an unsolved sort constraint, an index of clauses,
a sort theory, a boolean flag indicating whether the subsort
precheck can be applied, a flag store and a precedence.
RETURNS: A list of clauses inferred from the GivenClause by
SortResolution on the given clause.
MEMORY: A list of clauses is produced, where memory for the list
and the clauses is allocated.
***************************************************************/
{
LIST Result, TLits, RestLits;
int i, j, lc;
BOOL Hit;
TERM TAtom;
#ifdef CHECK
if (!clause_IsClause(GivenClause, Flags, Precedence) ||
!clause_HasTermSortConstraintLits(GivenClause)) {
misc_StartErrorReport();
misc_ErrorReport("\n In inf_ForwardSortResolution: Illegal input.\n");
misc_FinishErrorReport();
}
#endif
Result = list_Nil();
lc = clause_LastConstraintLitIndex(GivenClause);
Hit = FALSE;
i = clause_FirstLitIndex();
while (i <= lc && !Hit) {
TAtom = clause_GetLiteralAtom(GivenClause, i);
if (!term_IsVariable(term_FirstArgument(TAtom)))
Hit = TRUE;
else
i++;
}
if (!Hit)
return list_Nil();
/* added because of compiler warnings */
TAtom = clause_GetLiteralAtom(GivenClause, i);
/* Search the other T_i from <GivenClause> */
TLits = list_List((POINTER)i);
for (j = i+1; j <= lc; j++) {
if (term_FirstArgument(clause_GetLiteralAtom(GivenClause, j))
== term_FirstArgument(TAtom))
TLits = list_Cons((POINTER)j, TLits);
}
RestLits = list_Copy(TLits);
if (!Precheck ||
inf_SubsortPrecheck(GivenClause, TLits, NULL, Index, SortTheory)) {
Result = inf_ConstraintHyperResolvents(GivenClause, TLits, subst_Nil(),
RestLits, list_Nil(), Index, Flags,
Precedence);
}
list_Delete(RestLits);
list_Delete(TLits);
return Result;
}
LIST inf_BackwardEmptySort(CLAUSE GivenClause, st_INDEX Index,
SORTTHEORY SortTheory, BOOL Precheck,
FLAGSTORE Flags, PRECEDENCE Precedence)
/**************************************************************
INPUT: A clause with a solved sort constraint, an 'Index' of clauses,
a sort theory, a boolean flag indicating whether the subsort
precheck can be applied, a flag store and a precedence.
RETURNS: A list of clauses inferred from the GivenClause by
EmptySort with the given clause.
MEMORY: A list of clauses is produced, where memory for the list
and the clauses is allocated.
***************************************************************/
{
LIST result;
int i, ls;
#ifdef CHECK
if (!(clause_IsClause(GivenClause, Flags, Precedence)) ||
!clause_HasSolvedConstraint(GivenClause)) {
misc_StartErrorReport();
misc_ErrorReport("\n In inf_BackwardEmptySort: Illegal input.\n");
misc_FinishErrorReport();
}
#endif
result = list_Nil();
ls = clause_LastSuccedentLitIndex(GivenClause);
for (i = clause_FirstSuccedentLitIndex(GivenClause); i <= ls; i++) {
LITERAL pLit = clause_GetLiteral(GivenClause, i);
TERM pAtom = clause_LiteralAtom(pLit);
if (clause_LiteralGetFlag(pLit,STRICTMAXIMAL) &&
clause_LiteralIsSort(pLit)) {
LIST unifiers = st_GetUnifier(cont_LeftContext(),Index,cont_RightContext(),pAtom);
for ( ; !list_Empty(unifiers); unifiers = list_Pop(unifiers)){
if (term_IsAtom(list_Car(unifiers)) &&
term_IsVariable(term_FirstArgument(list_Car(unifiers)))) {
LIST litScan = sharing_NAtomDataList(list_Car(unifiers));
for ( ; !list_Empty(litScan); litScan = list_Cdr(litScan)){
LITERAL gLit = list_Car(litScan);
CLAUSE gClause = clause_LiteralOwningClause(gLit);
if (clause_LiteralGetIndex(gLit) < clause_FirstAntecedentLitIndex(gClause) &&
clause_GetFlag(gClause,WORKEDOFF) &&
clause_HasOnlyVarsInConstraint(gClause, Flags, Precedence)) {
TERM gAtom = clause_LiteralAtom(gLit);
SYMBOL var = term_TopSymbol(term_FirstArgument(gAtom));
int lc = clause_LastConstraintLitIndex(gClause);
int gi = clause_LiteralGetIndex(gLit);
BOOL varOccursNoMore;
int j, bound;
varOccursNoMore = TRUE;
bound = clause_LastSuccedentLitIndex(gClause);
for (j = clause_FirstAntecedentLitIndex(gClause);
(j <= bound) && varOccursNoMore;
j++) {
if (term_ContainsSymbol(clause_GetLiteralAtom(gClause, j), var))
varOccursNoMore = FALSE;
}
if (varOccursNoMore) {
LIST tLits, restLits;
/* Search the other T_i from <gClause> */
tLits = list_List((POINTER)gi);
restLits = list_Nil();
for (j = clause_FirstLitIndex(); j <= lc; j++) {
LITERAL tCand = clause_GetLiteral(gClause, j);
if (j != gi &&
term_FirstArgument(clause_LiteralAtom(tCand))
== term_FirstArgument(gAtom)) {
tLits = list_Cons((POINTER)j, tLits);
restLits = list_Cons((POINTER)j, restLits);
}
}
if (!Precheck ||
inf_SubsortPrecheck(gClause,tLits,pLit,Index,SortTheory)) {
CLAUSE pCopy = clause_Copy(GivenClause);
SYMBOL minVar = clause_MaxVar(gClause);
LIST foundLits = list_List(pLit);
SUBST leftSubst, rightSubst;
clause_RenameVarsBiggerThan(pCopy, minVar);
pAtom = clause_GetLiteralAtom(pCopy, i);
/* set, to adress the renamed term! */
cont_Check();
unify_UnifyNoOC(cont_LeftContext(), gAtom, cont_RightContext(), pAtom);
subst_ExtractUnifier(cont_LeftContext(), &leftSubst,
cont_RightContext(), &rightSubst);
cont_Reset();
subst_Delete(rightSubst);
result =
list_Nconc(inf_ConstraintHyperResolvents(gClause, tLits,
leftSubst,restLits,
foundLits, Index,
Flags, Precedence),
result);
list_Delete(foundLits);
subst_Delete(leftSubst);
clause_Delete(pCopy);
pAtom = clause_LiteralAtom(pLit);
/* reset to original clauses literal! */
} /* if Precheck */
list_Delete(tLits);
list_Delete(restLits);
}
}
}
}
}
}
}
return result;
}
LIST inf_ForwardEmptySort(CLAUSE GivenClause, st_INDEX Index,
SORTTHEORY SortTheory, BOOL Precheck, FLAGSTORE Flags,
PRECEDENCE Precedence)
/**************************************************************
INPUT: A clause, an index of clauses, a sort theory,
a boolean flag indicating whether the subsort
precheck can be applied, a flag store and a precedence.
The constraint of <GivenClause> is necessarily unsolved
RETURNS: A list of clauses inferred from the GivenClause by
EmptySort on the given clause.
MEMORY: A list of clauses is produced, where memory for the list
and the clauses is allocated.
***************************************************************/
{
LIST Result, TLits, RestLits;
int i, j, lc, ls;
BOOL Hit;
TERM TAtom;
SYMBOL Var;
#ifdef CHECK
if (clause_HasTermSortConstraintLits(GivenClause) ||
clause_HasSolvedConstraint(GivenClause)) {
misc_StartErrorReport();
misc_ErrorReport("\n In inf_ForwardEmptySort: Illegal input.\n");
misc_FinishErrorReport();
}
#endif
Result = list_Nil();
lc = clause_LastConstraintLitIndex(GivenClause);
Hit = FALSE;
i = clause_FirstLitIndex();
while (i <= lc && !Hit) {
TAtom = clause_GetLiteralAtom(GivenClause, i);
if (term_IsVariable(term_FirstArgument(TAtom))) {
Var = term_TopSymbol(term_FirstArgument(TAtom));
ls = clause_LastSuccedentLitIndex(GivenClause);
Hit = TRUE;
/* Check if the variable occurs in antecedent or succedent literals */
for (j = clause_FirstAntecedentLitIndex(GivenClause);
j <= ls && Hit; j++) {
if (term_ContainsSymbol(clause_GetLiteralAtom(GivenClause,j), Var))
Hit = FALSE; /* Variable occurs in antecedent/constraint literal */
}
}
if (!Hit)
i++;
}
if (!Hit)
return list_Nil();
TAtom = clause_GetLiteralAtom(GivenClause, i);
Var = term_TopSymbol(term_FirstArgument(TAtom));
/* Search the other T_i(t) literals */
TLits = list_List((POINTER)i);
for (j = i+1; j <= lc; j++) {
TERM TCand;
TCand = clause_GetLiteralAtom(GivenClause, j);
if (symbol_Equal(term_TopSymbol(term_FirstArgument(TCand)), Var))
TLits = list_Cons((POINTER)j, TLits);
}
RestLits = list_Copy(TLits);
if (!Precheck ||
inf_SubsortPrecheck(GivenClause, TLits, NULL, Index, SortTheory)) {
Result = inf_ConstraintHyperResolvents(GivenClause, TLits, subst_Nil(),
RestLits, list_Nil(), Index, Flags,
Precedence);
}
list_Delete(RestLits);
list_Delete(TLits);
return Result;
}
static LIST inf_GetForwardPartnerLits(LITERAL Literal, st_INDEX Index)
/**************************************************************
INPUT: A monadic literal, and an index of clauses.
RETURNS: A list of monadic succedent literals whose subterm
is unifiable with the (one) subterm of <Literal>.
The literals are strict maximal in their respective clauses,
the clauses are "WORKEDOFF" and either the subterm
is not a variable or the clause has an empty constraint.
MEMORY: Allocates memory for the list.
***************************************************************/
{
LIST result, unifiers, atomScan, litScan;
#ifdef CHECK
if (!clause_LiteralIsLiteral(Literal) || !clause_LiteralIsSort(Literal)) {
misc_StartErrorReport();
misc_ErrorReport("\n In inf_GetForwardPartnerLits: Illegal input.\n");
misc_FinishErrorReport();
}
#endif
result = list_Nil();
/* Search unifiers for the literal's subterm */
unifiers = st_GetUnifier(cont_LeftContext(), Index, cont_RightContext(),
term_FirstArgument(clause_LiteralAtom(Literal)));
for ( ; !list_Empty(unifiers); unifiers = list_Pop(unifiers)) {
if (!term_IsAtom(list_Car(unifiers))) { /* Can happen if arg is variable */
for (atomScan = term_SupertermList(list_Car(unifiers));
!list_Empty(atomScan);
atomScan = list_Cdr(atomScan)) {
TERM atomCand;
atomCand = (TERM) list_Car(atomScan);
if (term_IsDeclaration(atomCand)) {
/* We are looking for an unary atom */
for (litScan = sharing_NAtomDataList(atomCand);
!list_Empty(litScan);
litScan = list_Cdr(litScan)) {
LITERAL nextLit;
CLAUSE nextClause;
nextLit = list_Car(litScan);
nextClause = clause_LiteralOwningClause(nextLit);
if (clause_LiteralIsPositive(nextLit) &&
clause_LiteralGetFlag(nextLit,STRICTMAXIMAL) &&
clause_GetFlag(nextClause, WORKEDOFF) &&
(!term_IsVariable(list_Car(unifiers)) ||
clause_HasEmptyConstraint(nextClause)) &&
clause_HasSolvedConstraint(nextClause)) {
/* Add the literal from the copied clause */
result = list_Cons(nextLit, result);
}
} /* litScan */
} /* if IsAtom */
} /* atomScan */
} /* ! variable */
} /* unifiers */
return result;
}
static BOOL inf_LiteralsHaveSameSubtermAndAreFromSameClause(LITERAL L1, LITERAL L2)
/**************************************************************
INPUT: Two literals.
RETURNS: TRUE, if both literals have the same term and are
from the same clause, FALSE otherwise.
Since both literals are shared, pointer equality
is used to detect this.
This function is used by inf_GetBackwardPartnerLits().
***************************************************************/
{
return (term_FirstArgument(clause_LiteralAtom(L1))
== term_FirstArgument(clause_LiteralAtom(L2)) &&
clause_LiteralOwningClause(L1) == clause_LiteralOwningClause(L2));
}
static void inf_GetBackwardPartnerLits(LITERAL Literal, st_INDEX Index,
LIST* ConstraintLits, LIST* Unifiers,
BOOL IsFromEmptySort, FLAGSTORE Flags,
PRECEDENCE Precedence)
/**************************************************************
INPUT: A literal, an index of clauses, two pointers to lists,
a boolean value, a flag store and a precedence.
RETURNS:
MEMORY: Allocates memory for the list.
***************************************************************/
{
LIST candidates, atomScan, litScan;
LITERAL nextLit;
CLAUSE nextClause;
#ifdef CHECK
if (!clause_LiteralIsLiteral(Literal) || !clause_LiteralIsSort(Literal)) {
misc_StartErrorReport();
misc_ErrorReport("\n In inf_GetBackwardPartnerLits: Illegal input.\n");
misc_FinishErrorReport();
}
#endif
candidates = st_GetUnifier(cont_LeftContext(), Index, cont_RightContext(),
term_FirstArgument(clause_LiteralAtom(Literal)));
for ( ; !list_Empty(candidates); candidates = list_Pop(candidates)) {
if (!term_IsAtom(list_Car(candidates))) { /* May happen if arg is variable */
/* Consider variable unifiers only if called from BackwardEmptySort */
for (atomScan = term_SupertermList(list_Car(candidates));
!list_Empty(atomScan);
atomScan = list_Cdr(atomScan)) {
TERM atomCand;
atomCand = (TERM) list_Car(atomScan);
if (term_IsDeclaration(atomCand)) {
/* We are looking for unary atoms */
for (litScan = sharing_NAtomDataList(atomCand);
!list_Empty(litScan);
litScan = list_Cdr(litScan)) {
nextLit = list_Car(litScan);
nextClause = clause_LiteralOwningClause(nextLit);
if (clause_GetFlag(nextClause, WORKEDOFF)) {
if (clause_LiteralIsPositive(nextLit)) {
if (clause_LiteralGetFlag(nextLit,STRICTMAXIMAL) &&
(!term_IsVariable(list_Car(candidates)) ||
clause_HasEmptyConstraint(nextClause)) &&
clause_HasSolvedConstraint(nextClause) &&
!symbol_Equal(clause_LiteralPredicate(Literal),
clause_LiteralPredicate(nextLit))) {
/* Don't consider literals with same top symbol as given literal */
/* since the given clause must be part of any inference */
*Unifiers = list_Cons(nextLit, *Unifiers);
}
} else if (clause_LiteralGetIndex(nextLit) < clause_FirstAntecedentLitIndex(nextClause) &&
((!term_IsVariable(list_Car(candidates)) && !IsFromEmptySort) ||
(term_IsVariable(list_Car(candidates)) && IsFromEmptySort &&
clause_HasOnlyVarsInConstraint(nextClause,Flags, Precedence)))) {
*ConstraintLits = list_Cons(nextLit, *ConstraintLits);
}
}
} /* litScan */
}
} /* atomScan */
}
} /* candidates */
/* We have to avoid constraint literals from the same clause with the same
term or variable, since those would create the same result clause. */
*ConstraintLits =
list_DeleteDuplicates(*ConstraintLits,
(BOOL (*)(POINTER,POINTER)) inf_LiteralsHaveSameSubtermAndAreFromSameClause);
}
static void inf_MakeClausesDisjoint(CLAUSE GClause, LIST Literals)
/**************************************************************
INPUT: A clause and a non-empty list of literals.
EFFECT: All input clauses, those pointed to by the literals,
are variable disjointly renamed.
***************************************************************/
{
SYMBOL maxVar, maxCand;
CLAUSE lastClause;
maxVar = clause_MaxVar(GClause);
lastClause = clause_LiteralOwningClause(list_Car(Literals));
clause_RenameVarsBiggerThan(lastClause, maxVar);
Literals = list_Cdr(Literals);
for ( ; !list_Empty(Literals); Literals = list_Cdr(Literals)) {
CLAUSE actClause;
clause_UpdateMaxVar(lastClause);
maxCand = clause_MaxVar(lastClause);
maxVar = (symbol_GreaterVariable(maxVar,maxCand)? maxVar : maxCand);
actClause = clause_LiteralOwningClause(list_Car(Literals));
clause_RenameVarsBiggerThan(actClause, maxVar);
}
}
static void inf_CopyUnifierClauses(LIST Literals)
/**************************************************************
INPUT: A list of literals.
EFFECT: Replaces all literals by pointers to literals of copies
of the respective clauses.
***************************************************************/
{
for ( ; !list_Empty(Literals); Literals = list_Cdr(Literals)) {
CLAUSE actClause;
int i;
actClause = clause_LiteralOwningClause(list_Car(Literals));
i = clause_LiteralGetIndex(list_Car(Literals));
actClause = clause_Copy(actClause);