/Prelude-v18.0.0/List/shifted.dhall

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Combine a List of Lists, offsetting the index of each element by the number of elements in preceding lists

Examples

  shifted
Bool
[ [ { index = 0, value = True }
, { index = 1, value = True }
, { index = 2, value = True }
]
, [ { index = 0, value = False }, { index = 1, value = False } ]
, [ { index = 0, value = True }
, { index = 1, value = True }
, { index = 2, value = True }
, { index = 3, value = True }
]
]
≡ [ { index = 0, value = True }
, { index = 1, value = True }
, { index = 2, value = True }
, { index = 3, value = False }
, { index = 4, value = False }
, { index = 5, value = True }
, { index = 6, value = True }
, { index = 7, value = True }
, { index = 8, value = True }
]
  shifted Bool ([] : List (List { index : Natural, value : Bool }))
≡ ([] : List { index : Natural, value : Bool })

Source

{-|
Combine a `List` of `List`s, offsetting the `index` of each element by the
number of elements in preceding lists
-}
let shifted
: ∀(a : Type) →
List (List { index : Natural, value : a }) →
List { index : Natural, value : a }
= λ(a : Type) →
λ(kvss : List (List { index : Natural, value : a })) →
List/build
{ index : Natural, value : a }
( λ(list : Type) →
λ(cons : { index : Natural, value : a } → listlist) →
λ(nil : list) →
let result =
List/fold
(List { index : Natural, value : a })
kvss
{ count : Natural, diff : Natural → list }
( λ(kvs : List { index : Natural, value : a }) →
λ(y : { count : Natural, diff : Natural → list }) →
let length =
List/length { index : Natural, value : a } kvs

in { count = y.count + length
, diff =
λ(n : Natural) →
List/fold
{ index : Natural, value : a }
kvs
list
( λ ( kvOld
: { index : Natural, value : a }
) →
λ(z : list) →
let kvNew =
{ index = kvOld.index + n
, value = kvOld.value
}

in cons kvNew z
)
(y.diff (n + length))
}
)
{ count = 0, diff = λ(_ : Natural) → nil }

in result.diff 0
)

let example0 =
assert
: shifted
Bool
[ [ { index = 0, value = True }
, { index = 1, value = True }
, { index = 2, value = True }
]
, [ { index = 0, value = False }, { index = 1, value = False } ]
, [ { index = 0, value = True }
, { index = 1, value = True }
, { index = 2, value = True }
, { index = 3, value = True }
]
]
≡ [ { index = 0, value = True }
, { index = 1, value = True }
, { index = 2, value = True }
, { index = 3, value = False }
, { index = 4, value = False }
, { index = 5, value = True }
, { index = 6, value = True }
, { index = 7, value = True }
, { index = 8, value = True }
]

let example1 =
assert
: shifted Bool ([] : List (List { index : Natural, value : Bool }))
≡ ([] : List { index : Natural, value : Bool })

in shifted