def factorial

bend-collections@1.0.0.0 · src/math/generic.bend:456

import Base
import bend-collections@1.0.0.0/src/math/num.bend as N

456def factorial(~T: Data, ~op: N.Op<T> -> T, ~test: N.Test<T> -> Bool, +n: T) -> Result<&2, &2, N.NumError, T>:
457  ok(T, fact_go(~T, ~op, ~test, fuel(), op(N.One{}), n, (op(N.One{}), True{}), test(N.Lt{op(N.One{}), n})))