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

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Transform a Map by applying a function to each value

Examples

  map
Text
Natural
Bool
Natural/even
[ { mapKey = "A", mapValue = 2 }
, { mapKey = "B", mapValue = 3 }
, { mapKey = "C", mapValue = 5 }
]
≡ [ { mapKey = "A", mapValue = True }
, { mapKey = "B", mapValue = False }
, { mapKey = "C", mapValue = False }
]
  map
Text
Natural
Bool
Natural/even
([] : List { mapKey : Text, mapValue : Natural })
≡ ([] : List { mapKey : Text, mapValue : Bool })

Source

--| Transform a `Map` by applying a function to each value
let Map =
./Type.dhall sha256:210c7a9eba71efbb0f7a66b3dcf8b9d3976ffc2bc0e907aadfb6aa29c333e8ed
? ./Type.dhall

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

let List/map =
../List/map.dhall sha256:dd845ffb4568d40327f2a817eb42d1c6138b929ca758d50bc33112ef3c885680
? ../List/map.dhall

let map
: ∀(k : Type) → ∀(a : Type) → ∀(b : Type) → (a → b) → Map k a → Map k b
= λ(k : Type) →
λ(a : Type) →
λ(b : Type) →
λ(f : ab) →
λ(m : Map k a) →
List/map
(Entry k a)
(Entry k b)
( λ(before : Entry k a) →
{ mapKey = before.mapKey, mapValue = f before.mapValue }
)
m

let example0 =
assert
: map
Text
Natural
Bool
Natural/even
[ { mapKey = "A", mapValue = 2 }
, { mapKey = "B", mapValue = 3 }
, { mapKey = "C", mapValue = 5 }
]
≡ [ { mapKey = "A", mapValue = True }
, { mapKey = "B", mapValue = False }
, { mapKey = "C", mapValue = False }
]

let example1 =
assert
: map
Text
Natural
Bool
Natural/even
([] : List { mapKey : Text, mapValue : Natural })
≡ ([] : List { mapKey : Text, mapValue : Bool })

in map