Pattern Deriv(Pattern p, Pattern c)
{
switch (p.Type)
{
case PatternType.NotAllowed:
return(p);
case PatternType.Empty:
return(NotAllowed());
case PatternType.Ref:
return(c.Type == PatternType.Ref &&
p.Name == c.Name ? Empty() : NotAllowed());
case PatternType.OneOrMore:
return(Group(Deriv(p.p1, c), Optional(p)));
case PatternType.Choice:
return(Choice(Deriv(p.p1, c), Deriv(p.p2, c)));
case PatternType.And:
return(And(Deriv(p.p1, c), Deriv(p.p2, c)));
case PatternType.Not:
return(Not(Deriv(p.p1, c)));
case PatternType.Group:
if (c.Type == PatternType.Attribute)
{
return(Choice(Group(Deriv(p.p1, c), p.p2),
Group(p.p1, Deriv(p.p2, c))));
}
if (p.p1.Nullable)
{
return(Choice(Deriv(p.p2, c), Group(Deriv(p.p1, c), p.p2)));
}
return(Group(Deriv(p.p1, c), p.p2));
case PatternType.Text:
return(NotAllowed());
case PatternType.Attribute:
return(c.Type == PatternType.Attribute &&
p.Name == c.Name ? Optional(p) : NotAllowed());
case PatternType.Interleave:
return(Choice(Interleave(Deriv(p.p1, c), p.p2),
Interleave(p.p1, Deriv(p.p2, c))));
case PatternType.Define:
return(Define(p.Name, Deriv(p.p1, c)));
case PatternType.AnyName:
return(p);
case PatternType.LnName:
return(c.Type == PatternType.LnName &&
c.Name == p.Name ? Empty() : NotAllowed());
case PatternType.NsName:
return(c.Type == PatternType.NsName &&
c.Namespace == p.Namespace ? Empty() : NotAllowed());
default:
throw new Exception();
}
}
public State Simulate(Pattern elem)
{
if (Seen.Contains(elem))
{
return(Pattern2State [elem]);
}
var ElemState = new State()
{
IsNullable = elem.Nullable
};
var root = elem;
if (!Pattern2State.ContainsKey(root))
{
Pattern2State.Add(root, ElemState);
}
Queue <Pattern> queue = new Queue <Pattern> ();
queue.Enqueue(root);
var leaves = elem.DescendantNodesAndSelf().Where(x =>
x.Type == PatternType.Attribute ||
x.Type == PatternType.Ref).Distinct().ToList();
while (queue.Count > 0)
{
var current = queue.Dequeue();
var cstate = Pattern2State [current];
if (Seen.Contains(current))
{
continue;
}
current.DescendantNodesAndSelf()
.Where(x => x.Type == PatternType.Define)
.Where(x => x.Nullable)
.ToList()
.ForEach(x => cstate.NullableDefines.Add(x.Name));
Seen.Add(current);
foreach (var leaf in leaves)
{
var derived = Deriv(current, leaf);
if (derived.Type == PatternType.NotAllowed)
{
continue;
}
if (!Pattern2State.ContainsKey(derived))
{
Pattern2State.Add(derived, new State()
{
IsNullable = derived.Nullable
});
queue.Enqueue(derived);
}
var dstate = Pattern2State [derived];
if (leaf.Type == PatternType.Attribute)
{
if (leaf.Namespace.Length > 0)
{
cstate.AttrStates.Add("{" + leaf.Namespace + "}" + leaf.Name, dstate);
}
else
{
cstate.AttrStates.Add(leaf.Name, dstate);
}
}
else if (leaf.Type == PatternType.Ref)
{
cstate.ChildStates.Add(leaf.Name, dstate);
}
}
}
if (!Pattern2State.ContainsValue(ElemState))
{
throw new Exception();
}
return(ElemState);
}
Pattern Optional(Pattern p)
{
return(Choice(Empty(), p));
}