public override bool IsSubtypeOf(CatKind k)
{
if (k.IsAny())
{
return(true);
}
if (k is CatStackVar)
{
return(true);
}
if (!(k is CatTypeVector))
{
return(false);
}
CatTypeVector v1 = this;
CatTypeVector v2 = k as CatTypeVector;
while (!v1.IsEmpty() && !v2.IsEmpty())
{
CatKind t1 = v1.GetTop();
CatKind t2 = v2.GetTop();
if (!t1.IsSubtypeOf(t2))
{
return(false);
}
v1 = v1.GetRest();
v2 = v2.GetRest();
}
// v1 has to be at least as long to be a subtype
if (v1.IsEmpty() && !v2.IsEmpty())
{
return(false);
}
return(true);
}
public override bool Equals(CatKind k)
{
if (!(k is CatTypeVector))
{
return(false);
}
CatTypeVector v1 = this;
CatTypeVector v2 = k as CatTypeVector;
while (!v1.IsEmpty() && !v2.IsEmpty())
{
CatKind t1 = v1.GetTop();
CatKind t2 = v2.GetTop();
if (!t1.Equals(t2))
{
return(false);
}
v1 = v1.GetRest();
v2 = v2.GetRest();
}
if (!v1.IsEmpty())
{
return(false);
}
if (!v2.IsEmpty())
{
return(false);
}
return(true);
}