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36 lines
642 B
Haskell
36 lines
642 B
Haskell
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{-# LANGUAGE NoImplicitPrelude #-}
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module Hasura.GraphQL.NonEmptySeq
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( NESeq
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, (<|)
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, (|>)
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, init
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, head
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, toSeq
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) where
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import qualified Data.Sequence as Seq
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import Hasura.Prelude hiding (head)
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infixr 5 <|
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infixl 5 |>
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newtype NESeq a
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= NESeq { unNESeq :: (a, Seq.Seq a)}
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deriving (Show, Eq)
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init :: a -> NESeq a
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init a = NESeq (a, Seq.empty)
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head :: NESeq a -> a
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head = fst . unNESeq
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(|>) :: NESeq a -> a -> NESeq a
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(NESeq (h, l)) |> v = NESeq (h, l Seq.|> v)
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(<|) :: a -> NESeq a -> NESeq a
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v <| (NESeq (h, l)) = NESeq (v, h Seq.<| l)
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toSeq :: NESeq a -> Seq.Seq a
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toSeq (NESeq (v, l)) = v Seq.<| l
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