/Prelude-v21.1.0/Map/unpackOptionals.dhall

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Turn a Map k (Optional v) into a Map k v by dropping all entries with value None.

Examples

  unpackOptionals Text Text (toMap { foo = Some "bar", baz = None Text })
≡ toMap { foo = "bar" }

Source

--| Turn a `Map k (Optional v)` into a `Map k v` by dropping all
-- entries with value `None`.
let List/concatMap =
../List/concatMap.dhall sha256:3b2167061d11fda1e4f6de0522cbe83e0d5ac4ef5ddf6bb0b2064470c5d3fb64
? ../List/concatMap.dhall

let Map/Entry =
./Entry.dhall sha256:f334283bdd9cd88e6ea510ca914bc221fc2dab5fb424d24514b2e0df600d5346
? ./Entry.dhall

let Map/Type =
./Type.dhall sha256:210c7a9eba71efbb0f7a66b3dcf8b9d3976ffc2bc0e907aadfb6aa29c333e8ed
? ./Type.dhall

let unpackOptionals
: ∀(k : Type) → ∀(v : Type) → Map/Type k (Optional v) → Map/Type k v
= λ(k : Type) →
λ(v : Type) →
List/concatMap
(Map/Entry k (Optional v))
(Map/Entry k v)
( λ(e : Map/Entry k (Optional v)) →
merge
{ None = [] : Map/Type k v
, Some = λ(v : v) → [ { mapKey = e.mapKey, mapValue = v } ]
}
e.mapValue
)

let example0 =
assert
: unpackOptionals
Text
Text
(toMap { foo = Some "bar", baz = None Text })
≡ toMap { foo = "bar" }

in unpackOptionals