private static IEnumerable<Substitution> Conjunction(ISubstitutions firstSubst, ISubstitutions secondSubst)
{
var iter1 = firstSubst.GetEnumerator();
var iter2 = secondSubst.GetEnumerator();
var resSubst = GetEmptySubst();
bool firstNotEmpty = iter1.MoveNext(), secondNotEmpty = iter2.MoveNext();
while (firstNotEmpty && secondNotEmpty)
{
resSubst = resSubst.Unify(iter1.Current);
if (resSubst == null)
return null;
firstNotEmpty = iter1.MoveNext();
resSubst = resSubst.Unify(iter2.Current);
if (resSubst == null)
return null;
secondNotEmpty = iter2.MoveNext();
}
if (firstNotEmpty)
return ConjunctFinite(resSubst, new InfiniteSubstitutions(iter1.EnumerateFromCurrent())); //TODO Fabric
if (secondNotEmpty)
return ConjunctFinite(resSubst, new InfiniteSubstitutions(iter2.EnumerateFromCurrent())); //TODO Fabric
return resSubst;
}
private static IEnumerable<Substitution> ConjunctFinite(ISubstitutions finit, ISubstitutions potentialInfinite)
{
ISubstitutions res = potentialInfinite;
foreach (var subst in finit)
{
res = res.Unify(subst);
if (res == null)
return null;
}
return res;
}
private static IEnumerable<IEnumerable<Substitution>> Conjunction(ISubstitutions subst, Goal goal1, Goal goal2)
{
foreach (var firstSubst in goal1(subst))
{
foreach (var secondSubst in goal2(subst))
{
var resSubst = Conjunction(firstSubst, secondSubst);
if (resSubst != null)
yield return resSubst;
}
}
}
private static IEnumerable <IEnumerable <Substitution> > Conjunction(ISubstitutions subst, Goal goal1, Goal goal2)
{
foreach (var firstSubst in goal1(subst))
{
foreach (var secondSubst in goal2(subst))
{
var resSubst = Conjunction(firstSubst, secondSubst);
if (resSubst != null)
{
yield return(resSubst);
}
}
}
}
private static IEnumerable <Substitution> ConjunctFinite(ISubstitutions finit, ISubstitutions potentialInfinite)
{
ISubstitutions res = potentialInfinite;
foreach (var subst in finit)
{
res = res.Unify(subst);
if (res == null)
{
return(null);
}
}
return(res);
}
private static IEnumerable <Substitution> Conjunction(ISubstitutions firstSubst, ISubstitutions secondSubst)
{
var iter1 = firstSubst.GetEnumerator();
var iter2 = secondSubst.GetEnumerator();
var resSubst = GetEmptySubst();
bool firstNotEmpty = iter1.MoveNext(), secondNotEmpty = iter2.MoveNext();
while (firstNotEmpty && secondNotEmpty)
{
resSubst = resSubst.Unify(iter1.Current);
if (resSubst == null)
{
return(null);
}
firstNotEmpty = iter1.MoveNext();
resSubst = resSubst.Unify(iter2.Current);
if (resSubst == null)
{
return(null);
}
secondNotEmpty = iter2.MoveNext();
}
if (firstNotEmpty)
{
return(ConjunctFinite(resSubst, new InfiniteSubstitutions(iter1.EnumerateFromCurrent()))); //TODO Fabric
}
if (secondNotEmpty)
{
return(ConjunctFinite(resSubst, new InfiniteSubstitutions(iter2.EnumerateFromCurrent()))); //TODO Fabric
}
return(resSubst);
}
private static IEnumerable <IEnumerable <Substitution> > Disjunction(ISubstitutions subst, Goal goal1, Goal goal2)
{
var iter1 = goal1(subst).GetEnumerator();
var iter2 = goal2(subst).GetEnumerator();
bool firstNotEmpty = iter1.MoveNext(), secondNotEmpty = iter2.MoveNext();
while (firstNotEmpty || secondNotEmpty)
{
if (firstNotEmpty)
{
yield return(iter1.Current);
firstNotEmpty = iter1.MoveNext();
}
if (secondNotEmpty)
{
yield return(iter2.Current);
secondNotEmpty = iter2.MoveNext();
}
}
}
private static IEnumerable<IEnumerable<Substitution>> Disjunction(ISubstitutions subst, Goal goal1, Goal goal2)
{
var iter1 = goal1(subst).GetEnumerator();
var iter2 = goal2(subst).GetEnumerator();
bool firstNotEmpty = iter1.MoveNext(), secondNotEmpty = iter2.MoveNext();
while (firstNotEmpty || secondNotEmpty)
{
if (firstNotEmpty)
{
yield return iter1.Current;
firstNotEmpty = iter1.MoveNext();
}
if (secondNotEmpty)
{
yield return iter2.Current;
secondNotEmpty = iter2.MoveNext();
}
}
}
