28 lines
866 B
Plaintext
28 lines
866 B
Plaintext
(* binop : ('a -> 'a -> 'a) -> 'a list -> 'a list *)
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let binop op = function
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| b::a::r -> (op a b)::r
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| _ -> failwith "invalid expression"
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(* interp : float list -> string -> string * float list *)
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let interp s = function
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| "+" -> "add", binop ( +. ) s
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| "-" -> "subtr", binop ( -. ) s
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| "*" -> "mult", binop ( *. ) s
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| "/" -> "divide", binop ( /. ) s
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| "^" -> "exp", binop ( ** ) s
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| str -> "push", (float_of_string str) :: s
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(* interp_and_show : float list -> string -> float list *)
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let interp_and_show s inp =
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let op,s' = interp s inp in
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Printf.printf "%s\t%s\t" inp op;
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List.(iter (Printf.printf "%F ") (rev s'));
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print_newline ();
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s'
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(* rpn_eval : string -> float list *)
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let rpn_eval str =
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Printf.printf "Token\tAction\tStack\n";
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let ss = Str.(split (regexp_string " ") str) in
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List.fold_left interp_and_show [] ss
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