34 lines
938 B
Text
34 lines
938 B
Text
{-|
|
|
`listMin` returns the smallest element of a `List` or `None Natural` if the
|
|
`List` is empty
|
|
-}
|
|
let min =
|
|
missing
|
|
sha256:f25f9c462e4dbf0eb15f9ff6ac840c6e9c82255a7f4f2ab408bdab338e028710
|
|
? ./min.dhall
|
|
|
|
let Optional/map =
|
|
missing
|
|
sha256:501534192d988218d43261c299cc1d1e0b13d25df388937add784778ab0054fa
|
|
? ../Optional/map.dhall
|
|
|
|
let listMin
|
|
: List Natural → Optional Natural
|
|
= λ(xs : List Natural) →
|
|
Optional/map
|
|
Natural
|
|
Natural
|
|
( λ(n : Natural) →
|
|
if Natural/isZero n then n else List/fold Natural xs Natural min n
|
|
)
|
|
(List/head Natural xs)
|
|
|
|
let example0 = assert : listMin [ 0, 1 ] ≡ Some 0
|
|
|
|
let example1 = assert : listMin ([] : List Natural) ≡ None Natural
|
|
|
|
let example2 = assert : listMin [ 3, 2, 1 ] ≡ Some 1
|
|
|
|
let property0 = λ(n : Natural) → assert : listMin [ n ] ≡ Some n
|
|
|
|
in listMin
|