28 lines
497 B
Plaintext
28 lines
497 B
Plaintext
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(* -*- tuareg -*- *)
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module Let_syntax = struct
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type 'a t = T of 'a
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let map (T x) ~f = T (f x)
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let both (T x) (T y) = T (x, y)
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module Open_on_rhs = struct
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let return x = T x
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let f x ~(doc : string) = T (x, doc)
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end
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end
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let _ =
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[%map_open
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let x = return 42
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and y = f 42 in
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()]
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;;
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[%%expect
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Line _, characters 12-16:
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Error: This expression has type doc:string -> (int * string) Let_syntax.t
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but an expression was expected of type 'a Let_syntax.t
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|}]
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