bool isFinished()
{
bool isFinished(List <Shrub <Sum <Combinator, Variable> > > term, int arr, int i)
{
if (term.Count == 0)
{
return(arr == i);
}
var tail = term.Skip(1).ToList(); //TODO test me
return(term[0].Match(l => isFinished(tail, arr, i),
v => v.Match(c => isFinished(tail, arr, i), x =>
{
if ((int)x == i)
{
return isFinished(tail, arr, i - 1);
}
if ((int)x == -1)
{
return isFinished(tail, arr, i - 1) || isFinished(tail, arr, i);
}
return false;
})
));
}
goal.Match(l => isFinished(l, arrity, 0), v =>
{
if (arrity == 1)
{
return(v.Match(_ => false, x => (int)x <= 0));
}
return(false);
});
return(goal.Match <bool>(l =>
{
var ll = l.SkipWhile(s => s.Preorder().TrueForAll(v => v.Match(_ => true, x => (int)x == -1))); //ignore combinators at the start
return ll.Select((s, i) => (s, i)).ToList()
.TrueForAll(pi =>
pi.s.Match(_ => false,
v => v.Match(_ => false, x => (int)x == pi.i))); //the rest is just the variables in order
//TODO verify off by ones
}, x => x.Match(_ => false, i => (int)i == 0)));
}
public static BinaryTree <T> ToBinary <T>(Shrub <T> shrub)
{
return(shrub.Match <BinaryTree <T> >(l =>
{
int n = l.Count;
if (n == 0)
{
throw new Exception("Invalid shrub, empty parenthesis");
}
if (n == 1)
{
return ToBinary <T>(l[0]);
}
return BinaryTree <T> .Node(ToBinary <T>(Shrub <T> .Node(l.Take(n - 1).ToList())), ToBinary <T>(l[n - 1]));
}, x => BinaryTree <T> .Leaf(x)));
}