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Leonidas-from-XIV/gadtdecoder.ml

Last active October 10, 2017 12:56
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Mapping specifications into function signatures
Raw
gadtdecoder.ml
type _ elem =
| Int : int elem
| String : string elem
type (_, _) spec =
| [] : ('a, 'a) spec
| (::) : 'a elem * ('b, 'c) spec -> (('a -> 'b), 'c) spec
let decode_elem = function
| String -> fun x -> x
| Int -> int_of_string
let rec decode : type b c . (b, c) spec -> b -> 'd list -> c = function
| [] -> f ()
| _ :: rest -> decode rest
decode ["foo"; "32"] [String; Int] (fun str int -> Printf.sprintf "%d %s" int str)
|> print_endline
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