Documentation

Polymorphic version of length.

Defaults to Int, same as the non-polymorphic version, if return value is ambiguous.

>>> let list = [1..100] 

>>> :t length list length list :: Int 

>>> length list :: Word 100 >>> length list :: Int 100 >>> length list :: Word63 100 >>> length list :: Natural 100 >>> length list :: Integer 100 >>> length list :: Word8 ... ... error: ... Can not safely cast 'Morley.Prelude.Length.Length' to 'Word8': ... 'Morley.Prelude.Length.Length' is not a subtype of 'Word8' ... 

One caveat that with an unsuitable monomorphic type, length will also default to Int:

>>> length list :: Bool ... ... error: ... Couldn't match type ‘Bool’ with ‘Int’ ... 

However, this lets us avoid the issue with integral literals.