dhall-nix-lib/NonEmpty/shifted.dhall

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{-|
Combine a `NonEmpty` list of `NonEmpty` lists, offsetting the `index` of each
element by the number of elements in preceding lists
-}
let NonEmpty = ./Type.dhall
let NonEmpty/toList = ./toList.dhall
let List/map = ../List/map.dhall
let List/shifted = ../List/shifted.dhall
let shifted
: ∀(a : Type) →
NonEmpty (NonEmpty { index : Natural, value : a }) →
NonEmpty { index : Natural, value : a }
= λ(a : Type) →
λ(kvss : NonEmpty (NonEmpty { index : Natural, value : a })) →
{ head = kvss.head.head
, tail =
List/shifted
a
( [ kvss.head.tail ]
# List/map
(NonEmpty { index : Natural, value : a })
(List { index : Natural, value : a })
( λ(kvs : NonEmpty { index : Natural, value : a }) →
List/map
{ index : Natural, value : a }
{ index : Natural, value : a }
( λ(kv : { index : Natural, value : a }) →
{ index = kv.index + 1, value = kv.value }
)
(NonEmpty/toList { index : Natural, value : a } kvs)
)
kvss.tail
)
}
let example0 =
assert
: shifted
Bool
{ head =
{ head = { index = 0, value = True }
, tail =
[ { index = 1, value = True }, { index = 2, value = True } ]
}
, tail =
[ { head = { index = 0, value = False }
, tail = [ { index = 1, value = False } ]
}
, { head = { index = 0, value = True }
, tail =
[ { index = 1, value = True }
, { index = 2, value = True }
, { index = 3, value = True }
]
}
]
}
≡ { head = { index = 0, value = True }
, tail =
[ { 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
{ head =
{ head = { index = 0, value = True }
, tail = [] : List { index : Natural, value : Bool }
}
, tail = [] : List (NonEmpty { index : Natural, value : Bool })
}
≡ { head = { index = 0, value = True }
, tail = [] : List { index : Natural, value : Bool }
}
in shifted