def length

import bend-collections-laws-math@1.0.0.0/spec/lib/common.bend as Common

import Base

63def length(-A: Data, xs: List<&2, A>) -> Nat:
64  match xs:
65    case Nil{}:
66      0n
67    case Con{h, t}:
68      1n+length(A, t)

Uses (2)