RosettaCodeData/Task/Y-combinator/Ceylon/y-combinator-1.ceylon

23 lines
620 B
Ceylon

Result(*Args) y1<Result,Args>(
Result(*Args)(Result(*Args)) f)
given Args satisfies Anything[] {
class RecursiveFunction(o) {
shared Result(*Args)(RecursiveFunction) o;
}
value r = RecursiveFunction((RecursiveFunction w)
=> f(flatten((Args args) => w.o(w)(*args))));
return r.o(r);
}
value factorialY1 = y1((Integer(Integer) fact)(Integer x)
=> if (x > 1) then x * fact(x - 1) else 1);
value fibY1 = y1((Integer(Integer) fib)(Integer x)
=> if (x > 2) then fib(x - 1) + fib(x - 2) else 2);
print(factorialY1(10)); // 3628800
print(fibY1(10)); // 110