public void SecondFunctorLawHoldsForSelectLeaf(IRoseTree <int, string> t)
{
bool f(int x) => x % 2 == 0;
int g(string s) => s.Length;
Assert.Equal(
t.SelectLeaf(x => f(g(x))),
t.SelectLeaf(g).SelectLeaf(f));
}
public void ConsistencyLawHolds(IRoseTree <int, string> t)
{
DateTime f(int i) => new DateTime(i);
bool g(string s) => string.IsNullOrWhiteSpace(s);
Assert.Equal(t.SelectBoth(f, g), t.SelectLeaf(g).SelectNode(f));
Assert.Equal(
t.SelectNode(f).SelectLeaf(g),
t.SelectLeaf(g).SelectNode(f));
}
public void SelectLeafObeysFirstFunctorLaw(IRoseTree <int, string> t)
{
Assert.Equal(t, t.SelectLeaf(Id));
}
// Functor
public static IRoseTree <N, L1> Select <N, L, L1>(
this IRoseTree <N, L> source,
Func <L, L1> selector)
{
return(source.SelectLeaf(selector));
}