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74 lines
1.7 KiB
OCaml
74 lines
1.7 KiB
OCaml
(*
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MSAT is free software, using the Apache license, see file LICENSE
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Copyright 2014 Guillaume Bury
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Copyright 2014 Simon Cruanes
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*)
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exception Invalid_var
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type var = string
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type formula =
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| Prop of int
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| Equal of var * var
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| Distinct of var * var
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type t = formula
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type proof = unit
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let dummy = Prop 0
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let max_fresh = ref 0
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let fresh () =
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incr max_fresh;
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Prop (2 * !max_fresh + 1)
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let mk_prop i =
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if i <> 0 && i < max_int / 2 then Prop (2 * i)
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else raise Invalid_var
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let mk_var i =
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if i <> "" then i
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else raise Invalid_var
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let mk_eq i j = Equal (mk_var (min i j), mk_var (max i j))
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let mk_neq i j = Distinct (mk_var (min i j), mk_var (max i j))
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let neg = function
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| Prop i -> Prop (-i)
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| Equal (a, b) -> Distinct (a, b)
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| Distinct (a, b) -> Equal (a, b)
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let norm = function
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| Prop i -> Prop (abs i), i < 0
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| Equal (a, b) -> Equal (a, b), false
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| Distinct (a, b) -> Equal (a, b), true
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(* Only used after normalisation, so usual functions should work *)
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let hash = Hashtbl.hash
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let equal = (=)
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let compare = Pervasives.compare
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let s = Hstring.make ""
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let label _ = s
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let add_label _ _ = ()
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let print fmt = function
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| Prop i -> Format.fprintf fmt "%s%s%d" (if i < 0 then "¬ " else "") (if i mod 2 = 0 then "v" else "f") ((abs i) / 2)
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| Equal (a, b) -> Format.fprintf fmt "%s = %s" a b
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| Distinct (a, b) -> Format.fprintf fmt "%s ≠ %s" a b
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module Term = struct
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type t = var
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let hash = Hashtbl.hash
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let equal = (=)
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let compare = Pervasives.compare
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let print fmt t = Format.fprintf fmt "%s" t
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end
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module Formula = struct
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type t = formula
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let hash = Hashtbl.hash
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let equal = (=)
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let compare = Pervasives.compare
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let print = print
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end
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