39 lines
1.2 KiB
Text
39 lines
1.2 KiB
Text
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Transform each value in a `List` to `Text` and then concatenate them with a
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separator in between each value
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-}
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let Status = < Empty | NonEmpty : Text >
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let concatMapSep
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: ∀(separator : Text) → ∀(a : Type) → (a → Text) → List a → Text
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= λ(separator : Text) →
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λ(a : Type) →
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λ(f : a → Text) →
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λ(elements : List a) →
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let status =
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List/fold
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a
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elements
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Status
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( λ(x : a) →
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λ(status : Status) →
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merge
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{ Empty = Status.NonEmpty (f x)
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, NonEmpty =
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λ(result : Text) →
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Status.NonEmpty (f x ++ separator ++ result)
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}
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status
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)
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Status.Empty
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in merge { Empty = "", NonEmpty = λ(result : Text) → result } status
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let example0 =
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assert : concatMapSep ", " Natural Natural/show [ 0, 1, 2 ] ≡ "0, 1, 2"
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let example1 =
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assert : concatMapSep ", " Natural Natural/show ([] : List Natural) ≡ ""
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in concatMapSep
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