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OCaml

(***********************************************************************)
(* *)
(* Heptagon *)
(* *)
(* Gwenael Delaval, LIG/INRIA, UJF *)
(* Leonard Gerard, Parkas, ENS *)
(* Adrien Guatto, Parkas, ENS *)
(* Cedric Pasteur, Parkas, ENS *)
(* *)
(* Copyright 2012 ENS, INRIA, UJF *)
(* *)
(* This file is part of the Heptagon compiler. *)
(* *)
(* Heptagon is free software: you can redistribute it and/or modify it *)
(* under the terms of the GNU General Public License as published by *)
(* the Free Software Foundation, either version 3 of the License, or *)
(* (at your option) any later version. *)
(* *)
(* Heptagon is distributed in the hope that it will be useful, *)
(* but WITHOUT ANY WARRANTY; without even the implied warranty of *)
(* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *)
(* GNU General Public License for more details. *)
(* *)
(* You should have received a copy of the GNU General Public License *)
(* along with Heptagon. If not, see <http://www.gnu.org/licenses/> *)
(* *)
(***********************************************************************)
(* removing automata statements *)
(* TODO deal correctly with [stateful] and [unsafe] *)
open Misc
open Types
open Names
open Idents
open Heptagon
open Hept_utils
open Hept_mapfold
open Initial
open Modules
type var = S | NS | R | NR | PNR
let fresh = Idents.gen_fresh "automata"
(function S -> "s" | NS -> "ns" | R -> "r" | NR -> "nr" | PNR -> "pnr")
let mk_var_exp n ty =
mk_exp (Evar n) ty ~linearity:Linearity.Ltop
let mk_pair e1 e2 =
mk_exp (mk_op_app Etuple [e1;e2]) (Tprod [e1.e_ty; e2.e_ty])
~linearity:(Linearity.Ltuple [Linearity.Ltop; Linearity.Ltop])
let mk_reset_equation eq_list e =
mk_equation (Ereset (mk_block eq_list, e))
let mk_switch_equation e l =
mk_equation (Eswitch (e, l))
let mk_exp_fby_false e =
mk_exp (Epre (Some (mk_static_bool false), e))
(Tid Initial.pbool) ~linearity:Linearity.Ltop
let mk_constructor constr ty =
mk_static_exp ty (Sconstructor constr)
(* Be sure that [initial] is of the right type [e.e_ty] before using this *)
let mk_exp_fby_state initial e =
{ e with e_desc = Epre (Some (mk_constructor initial e.e_ty), e) }
(* the list of enumerated types introduced to represent states *)
let state_type_dec_list = ref []
(* create and add to the env the constructors corresponding to a name state *)
let intro_state_constr type_name state state_env =
let n = String.capitalize (Names.shortname type_name) ^ "_" ^ state in
let c = Modules.fresh_constr "automata" n in
Modules.add_constrs c type_name; NamesEnv.add state c state_env
(* create and add the the global env and to state_type_dec_list
a type corresponding to the state env*)
let intro_type type_name state_env =
let state_constrs = NamesEnv.fold (fun _ c c_l -> c::c_l) state_env [] in
(* Add the new type to the env *)
Modules.add_type type_name (Signature.Tenum state_constrs);
(* Add the new type to the types to add to the Ast *)
state_type_dec_list :=
Ptype (mk_type_dec type_name (Type_enum state_constrs)) :: !state_type_dec_list
(** Allows to classify an automaton :
Moore automatons doesn't have strong transitions,
Mealy automatons may have some. *)
let no_strong_transition state_handlers =
let handler no_strong { s_unless = l } = no_strong & (l = []) in
List.fold_left handler true state_handlers
let translate_automaton v eq_list handlers =
let type_name = Modules.fresh_type "automata" "st" in
(* the state env associate a name to a qualified constructor *)
let state_env =
List.fold_left
(fun env { s_state = n } -> intro_state_constr type_name n env)
NamesEnv.empty handlers in
intro_type type_name state_env;
let tstatetype = Tid type_name in
(* The initial state constructor *)
let initial = (NamesEnv.find (List.hd handlers).s_state state_env) in
let statename = fresh S in
let next_statename = fresh NS in
let resetname = fresh R in
let next_resetname = fresh NR in
let pre_next_resetname = fresh PNR in
let name n = NamesEnv.find n state_env in
let state n =
mk_exp (Econst (mk_constructor (name n) tstatetype)) tstatetype ~linearity:Linearity.Ltop
in
let statevar n = mk_var_exp n tstatetype in
let boolvar n = mk_var_exp n (Tid Initial.pbool) in
let escapes n s rcont =
let escape { e_cond = e; e_reset = r; e_next_state = n } cont =
mk_ifthenelse e (mk_pair (state n) (if r then dtrue else dfalse)) cont
in
List.fold_right escape s (mk_pair (state n) rcont)
in
let strong { s_state = n; s_unless = su } =
let rst_vd = mk_var_dec resetname (Tid Initial.pbool) Linearity.Ltop in
let defnames = Env.add resetname rst_vd Env.empty in
let state_vd = mk_var_dec statename tstatetype Linearity.Ltop in
let defnames = Env.add statename state_vd defnames in
let st_eq = mk_simple_equation
(Etuplepat[Evarpat(statename); Evarpat(resetname)])
(escapes n su (boolvar pre_next_resetname)) in
mk_block ~defnames:defnames [mk_reset_equation [st_eq]
(boolvar pre_next_resetname)]
in
let weak { s_state = n; s_block = b; s_until = su } =
let nextrst_vd = mk_var_dec next_resetname (Tid Initial.pbool) Linearity.Ltop in
let defnames = Env.add next_resetname nextrst_vd b.b_defnames in
let nextstate_vd = mk_var_dec next_statename tstatetype Linearity.Ltop in
let defnames = Env.add next_statename nextstate_vd defnames in
let ns_eq = mk_simple_equation
(Etuplepat[Evarpat(next_statename); Evarpat(next_resetname)])
(escapes n su dfalse) in
{ b with b_equs =
[mk_reset_equation (ns_eq::b.b_equs) (boolvar resetname)];
(* (or_op (boolvar pre_next_resetname) (boolvar resetname))]; *)
b_defnames = defnames;
}
in
let v =
(mk_var_dec next_statename tstatetype ~linearity:Linearity.Ltop) ::
(mk_var_dec resetname (Tid Initial.pbool) ~linearity:Linearity.Ltop) ::
(mk_var_dec next_resetname (Tid Initial.pbool) ~linearity:Linearity.Ltop) ::
(mk_var_dec pre_next_resetname (Tid Initial.pbool) ~linearity:Linearity.Ltop) :: v in
if no_strong_transition handlers
then (* Only weak transitions : a Moore automaton. *)
let switch_e = mk_exp_fby_state initial (statevar next_statename) in
let switch_handlers =
List.map (fun ({ s_state = n } as case) ->
{ w_name = name n; w_block = weak case })
handlers in
let switch_eq = mk_switch_equation switch_e switch_handlers in
let nr_eq =
mk_simple_equation (Evarpat pre_next_resetname)
(mk_exp_fby_false (boolvar (next_resetname))) in
let pnr_eq =
mk_simple_equation (Evarpat resetname) (boolvar pre_next_resetname) in
v, switch_eq :: nr_eq :: pnr_eq :: eq_list
else (* General case,
two switch to generate statename variable used and defined *)
let v = (mk_var_dec statename tstatetype ~linearity:Linearity.Ltop) :: v in
let ns_switch_e = mk_exp_fby_state initial (statevar next_statename) in
let ns_switch_handlers =
List.map (fun ({ s_state = n } as case) ->
{ w_name = name n; w_block = strong case })
handlers in
let ns_switch_eq = mk_switch_equation ns_switch_e ns_switch_handlers in
let switch_e = statevar statename in
let switch_handlers =
List.map (fun ({ s_state = n } as case) ->
{ w_name = name n; w_block = weak case })
handlers in
let switch_eq = mk_switch_equation switch_e switch_handlers in
let pnr_eq =
mk_simple_equation (Evarpat pre_next_resetname)
(mk_exp_fby_false (boolvar (next_resetname))) in
v, ns_switch_eq :: switch_eq :: pnr_eq :: eq_list
let rec eq funs (v, eq_list) eq =
let eq, (v, eq_list) = Hept_mapfold.eq funs (v, eq_list) eq in
match eq.eq_desc with
| Eautomaton state_handlers ->
eq, translate_automaton v eq_list state_handlers
| _ -> eq, (v, eq::eq_list)
let block funs acc b =
let b, (v, acc_eq_list) = Hept_mapfold.block funs ([], []) b in
{ b with b_local = v @ b.b_local; b_equs = acc_eq_list }, acc
let program p =
let funs = { Hept_mapfold.defaults
with eq = eq; block = block } in
let p, _ = Hept_mapfold.program_it funs ([],[]) p in
{ p with p_desc = !state_type_dec_list @ p.p_desc }