67 lines
1.6 KiB
OCaml
67 lines
1.6 KiB
OCaml
open Format
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open Names
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open Misc
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type linearity_var = name
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type linearity =
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| Ltop
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| Lat of linearity_var
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| Lvar of linearity_var (*a linearity var, used in functions sig *)
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| Ltuple of linearity list
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module LinearitySet = Set.Make(struct
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type t = linearity
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let compare = compare
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end)
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(** Returns a linearity object from a linearity list. *)
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let prod = function
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| [l] -> l
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| l -> Ltuple l
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let linearity_list_of_linearity = function
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| Ltuple l -> l
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| l -> [l]
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let rec lin_skeleton lin = function
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| Types.Tprod l -> Ltuple (List.map (lin_skeleton lin) l)
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| _ -> lin
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(** Same as Misc.split_last but on a linearity. *)
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let split_last_lin = function
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| Ltuple l ->
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let l, acc = split_last l in
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Ltuple l, acc
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| l ->
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Ltuple [], l
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let rec is_not_linear = function
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| Ltop -> true
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| Ltuple l -> List.for_all is_not_linear l
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| _ -> false
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exception UnifyFailed
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(** Unifies lin with expected_lin and returns the result
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of the unification. Applies subtyping and instantiate linearity vars. *)
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let rec unify_lin expected_lin lin =
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match expected_lin,lin with
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| Ltop, Lat _ -> Ltop
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| Ltop, Lvar _ -> Ltop
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| Lat r1, Lat r2 when r1 = r2 -> Lat r1
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| Ltop, Ltop -> Ltop
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| Ltuple l1, Ltuple l2 -> Ltuple (List.map2 unify_lin l1 l2)
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| Lvar _, Lat r -> Lat r
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| Lat r, Lvar _ -> Lat r
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| _, _ -> raise UnifyFailed
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let rec lin_to_string = function
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| Ltop -> "at T"
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| Lat r -> "at "^r
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| Lvar r -> "at _"^r
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| Ltuple l_list -> String.concat ", " (List.map lin_to_string l_list)
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let print_linearity ff l =
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fprintf ff " %s" (lin_to_string l)
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