134 lines
3.6 KiB
OCaml
134 lines
3.6 KiB
OCaml
(**************************************************************************)
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(* *)
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(* Heptagon *)
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(* *)
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(* Author : Marc Pouzet *)
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(* Organization : Demons, LRI, University of Paris-Sud, Orsay *)
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(* *)
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(**************************************************************************)
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open Names
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open Idents
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open Types
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type ct =
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| Ck of ck
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| Cprod of ct list
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and ck =
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| Cbase
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| Cvar of link ref
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| Con of ck * constructor_name * var_ident
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and link =
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| Cindex of int
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| Clink of ck
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exception Unify
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let invalid_clock = Cprod []
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let index = ref 0
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let gen_index () = (incr index; !index)
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(** returns a new clock variable *)
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let fresh_clock () = Cvar { contents = Cindex (gen_index ()); }
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(** returns a new clock type corresponding to the data type [ty] *)
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let rec fresh_ct ty = match ty with
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| Tprod ty_list ->
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(match ty_list with
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| [] -> Ck (fresh_clock())
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| _ -> Cprod (List.map fresh_ct ty_list))
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| Tarray (t, _) -> fresh_ct t
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| Tid _ | Tinvalid -> Ck (fresh_clock())
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(** returns the canonic (short) representant of a [ck]
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and update it to this value. *)
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let rec ck_repr ck = match ck with
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| Cbase | Con _
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| Cvar { contents = Cindex _ } -> ck
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| Cvar (({ contents = Clink ck } as link)) ->
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let ck = ck_repr ck in
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link.contents <- Clink ck;
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ck
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(** verifies that index is fresh in ck. *)
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let rec occur_check index ck =
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let ck = ck_repr ck in
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match ck with
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| Cbase -> ()
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| Cvar { contents = Cindex n } when index <> n -> ()
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| Con (ck, _, _) -> occur_check index ck
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| _ -> raise Unify
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(** unify ck *)
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and unify_ck ck1 ck2 =
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let ck1 = ck_repr ck1 in
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let ck2 = ck_repr ck2 in
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if ck1 == ck2 then ()
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else
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match (ck1, ck2) with
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| Cbase, Cbase -> ()
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| Cvar { contents = Cindex n1 }, Cvar { contents = Cindex n2 } when n1 = n2 -> ()
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| Con (ck1, c1, n1), Con (ck2, c2, n2) when (c1 = c2) & (n1 = n2) ->
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unify_ck ck1 ck2
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| Cvar ({ contents = Cindex n } as v), ck
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| ck, Cvar ({ contents = Cindex n } as v) ->
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occur_check n ck;
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v.contents <- Clink ck
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| _ -> raise Unify
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(** unify ct *)
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let rec unify t1 t2 =
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if t1 == t2 then () else
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match (t1, t2) with
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| (Ck (Cbase | Cvar { contents = Cindex _; }), Cprod [])
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| (Cprod [], Ck (Cbase | Cvar { contents = Cindex _; })) -> ()
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| (Ck ck1, Ck ck2) -> unify_ck ck1 ck2
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| (Cprod t1_list, Cprod t2_list) -> unify_list t1_list t2_list
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| _ -> raise Unify
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and unify_list t1_list t2_list =
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try List.iter2 unify t1_list t2_list
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with _ -> raise Unify
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let rec skeleton ck = function
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| Tprod ty_list ->
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(match ty_list with
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| [x] -> Ck ck
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| l -> Cprod (List.map (skeleton ck) l))
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| Tarray _ | Tid _ | Tinvalid -> Ck ck
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let unprod ct =
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let rec f acc ct = match ct with
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| Ck ck -> ck::acc
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| Cprod ct_l -> List.fold_left f acc ct_l
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in
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f [] ct
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let prod ck_l = match ck_l with
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| [ck] -> Ck ck
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| _ -> Cprod (List.map (fun ck -> Ck ck) ck_l)
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let rec root_ck_of ck = match ck_repr ck with
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| Cbase
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| Cvar { contents = Cindex _ } -> ck
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| Con(ck,_,_) -> root_ck_of ck
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| Cvar { contents = Clink _ } -> Misc.internal_error "Clocks, wrong repr"
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let rec last_clock ct = match ct with
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| Ck ck -> ck
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| Cprod l -> last_clock (Misc.last_element l)
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