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26 lines
578 B
Idris
26 lines
578 B
Idris
module Data.Singleton
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||| The type containing only a particular value.
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||| This is useful for calculating type-level information at runtime.
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public export
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data Singleton : a -> Type where
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Val : (x : a) -> Singleton x
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public export %inline
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unVal : Singleton {a} x -> a
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unVal $ Val x = x
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public export %inline
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(.unVal) : Singleton {a} x -> a
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(.unVal) = unVal
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-- pure and <*> implementations for idiom bracket notation
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public export
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pure : (x : a) -> Singleton x
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pure = Val
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public export
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(<*>) : Singleton f -> Singleton x -> Singleton (f x)
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Val f <*> Val x = Val (f x)
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