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30 lines
477 B
Idris
30 lines
477 B
Idris
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data NonEmpty : List a -> Type where
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IsNonEmpty : NonEmpty (x :: xs)
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head : (xs : List a) -> NonEmpty xs => a
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head (x :: xs) = x
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failing "Can't find an implementation for NonEmpty xs."
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myHead : List a -> a
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myHead xs = head xs
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failing "Can't find
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an implementation
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for NonEmpty xs."
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myHead : List a -> a
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myHead xs = head xs
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failing "Can't
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find
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an implementation
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for NonEmpty xs."
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myHead : List a -> a
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myHead xs = head xs
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