public override PathCond Or(PathCond other) {
if (other is CachedAtom && conds.Contains(((CachedAtom)other).Negate())) {
// Reduce Or(OR(...,e,...), NOT(e)) and Or(OR(...,NOT(e),...), e) to TRUE
return TRUE;
}
else if (other is Disj) {
HashList<PathCond> result = new HashList<PathCond>();
result.AddAll(conds);
foreach (PathCond cond in ((Disj)other).conds) {
if (cond is CachedAtom && conds.Contains((cond as CachedAtom).Negate())) {
// Reduce Or(OR(...,e,...),OR(...,NOT(e),...)) to TRUE
// and Or(OR(...,NOT(e),...),OR(...,e,...)) to TRUE
return TRUE;
}
result.Add(cond);
}
return Disj.Make(result.ToArray());
}
else if (other is Conj) {
if (((Conj)other).conds.Contains(this)) {
// Reduce (pi | (p1 & ... & pn)) to pi
return this;
}
else {
if (((Conj)other).conds.Any(cond => conds.Contains(cond))) {
return this;
}
}
return Disj.Make(AddItem(this.conds, other));
}
else {
return Disj.Make(AddItem(this.conds, other));
}
}
protected static PathCond[] AddItem(IEnumerable <PathCond> set, PathCond item)
{
HashList <PathCond> result = new HashList <PathCond>();
result.AddAll(set);
result.Add(item);
return(result.ToArray());
}
public override PathCond Or(PathCond other)
{
if (other is CachedAtom && conds.Contains(((CachedAtom)other).Negate()))
{
// Reduce Or(OR(...,e,...), NOT(e)) and Or(OR(...,NOT(e),...), e) to TRUE
return(TRUE);
}
else if (other is Disj)
{
HashList <PathCond> result = new HashList <PathCond>();
result.AddAll(conds);
foreach (PathCond cond in ((Disj)other).conds)
{
if (cond is CachedAtom && conds.Contains((cond as CachedAtom).Negate()))
{
// Reduce Or(OR(...,e,...),OR(...,NOT(e),...)) to TRUE
// and Or(OR(...,NOT(e),...),OR(...,e,...)) to TRUE
return(TRUE);
}
result.Add(cond);
}
return(Disj.Make(result.ToArray()));
}
else if (other is Conj)
{
if (((Conj)other).conds.Contains(this))
{
// Reduce (pi | (p1 & ... & pn)) to pi
return(this);
}
else
{
if (((Conj)other).conds.Any(cond => conds.Contains(cond)))
{
return(this);
}
}
return(Disj.Make(AddItem(this.conds, other)));
}
else
{
return(Disj.Make(AddItem(this.conds, other)));
}
}
