Source file proc.ml
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open! Core_kernel
open! Import
open Component
open Incremental.Let_syntax
module T = struct
type ('input, 'model, 'action, 'result, 'incr, 'event) unpacked +=
| Abstraction :
{ t : (unit, 'model, 'action, 'result, 'incr, 'event) unpacked
; type_id : 'a Type_equal.Id.t
}
-> ('a, 'model, 'action, 'result, 'incr, 'event) unpacked
| Var :
{ type_id : 'a Type_equal.Id.t }
-> (unit, unit, Nothing.t, 'a, 'incr, 'event) unpacked
let eval (type i m a r incr event) : (i, m, a, r, incr, event) eval_type =
fun ~input ~old_model ~model ~inject ~action_type_id ~environment ~incr_state t ->
match t with
| Abstraction { t; type_id } ->
let return = Incremental.return incr_state in
let environment = Environment.add_exn environment type_id input in
eval_ext
~input:(return ())
~old_model
~model
~inject
~action_type_id
~environment
~incr_state
t
| Var { type_id } ->
let%map read = Environment.find_exn environment type_id in
Snapshot.create ~result:read ~apply_action:(fun ~schedule_event:_ ->
Nothing.unreachable_code)
| _ -> assert false
;;
let abstraction (Packed.T { unpacked; model; action_type_id }) ~type_id =
Packed.T { unpacked = Abstraction { t = unpacked; type_id }; model; action_type_id }
;;
let var (type a) (type_id : a Type_equal.Id.t) : (_, a, 'incr, 'event) Packed.t =
Packed.T
{ unpacked = Var { type_id }
; action_type_id = nothing_type_id
; model = Packed.unit_model_info
}
;;
let sexp_of_unpacked (type i m a r) (component : (i, m, a, r, _, _) unpacked) =
match component with
| Abstraction { t; type_id = _ } -> [%sexp Proc_abstraction (t : unpacked)]
| Var { type_id = _ } -> [%sexp Proc_var]
| _ -> assert false
;;
let visit
(type i r incr event)
(T { unpacked; action_type_id; model } as packed : (i, r, incr, event) Packed.t)
visitor
=
match unpacked with
| Abstraction { t; type_id } ->
let visited =
visit_ext (Packed.T { unpacked = t; action_type_id; model }) visitor
in
(visitor.visit (abstraction visited ~type_id) : (i, _, _, _) Packed.t)
| Var _ -> visitor.visit packed
| _ -> assert false
;;
end
include T
let () =
Component.define
(module struct
include T
let extension_constructor = [%extension_constructor Abstraction]
end)
;;
let () =
Component.define
(module struct
include T
let extension_constructor = [%extension_constructor Var]
end)
;;
module Val = struct
type 'a t =
| Constant : 'a -> 'a t
| Named : 'a Type_equal.Id.t -> 'a t
| Map :
{ t : 'a t
; f : 'a -> 'b
}
-> 'b t
| Map2 :
{ a : 'a t
; b : 'b t
; f : 'a -> 'b -> 'c
}
-> 'c t
| Both :
{ a : 'a t
; b : 'b t
}
-> ('a * 'b) t
module T = Applicative.Make_using_map2 (struct
type nonrec 'a t = 'a t
let map = `Custom (fun t ~f -> Map { t; f })
let map2 a b ~f = Map2 { a; b; f }
let return a = Constant a
end)
include T
module Open_on_rhs_intf = struct
module type S = sig end
end
module Let_syntax = struct
include T
module Let_syntax = struct
include T
let both a b = Both { a; b }
module Open_on_rhs = struct end
end
end
end
module Computation = struct
type ('a, 'incr, 'event) t = (unit, 'a, 'incr, 'event) Packed.t
end
let proc f =
let type_id = Type_equal.Id.create ~name:"some variable" sexp_of_opaque in
abstraction ~type_id (f (Val.Named type_id))
;;
let sub c ~f = Compose.compose c (proc f)
let rec return : type a. a Val.t -> (a, _, _) Computation.t = function
| Val.Constant a -> Const.const a
| Val.Named type_id -> var type_id
| Val.Map { t; f } -> Mapn.map (return t) ~f
| Val.Map2 { a; b; f } -> Mapn.map2 (return a) (return b) ~f
| Val.Both { a; b } -> Mapn.both (return a) (return b)
;;
let apply c v = Compose.compose (return v) c
let apply_unit c = Compose.compose (Const.const ()) c
let ignore_input = Map_input.map_input ~f:Fn.ignore
let if_ cond ~then_ ~else_ =
Compose.compose
(return cond)
(Switch.if_ Fn.id ~then_:(ignore_input then_) ~else_:(ignore_input else_))
;;
let enum mdl ~match_ ~with_ =
Compose.compose
(return match_)
(Switch.enum mdl ~which:Fn.id ~handle:(fun a -> ignore_input (with_ a)))
;;