Refactor operator system

This commit:
- removes unused functions
- refactors operator overloading & auto-coercion system
- changes type signitures of operators
- incorperates unary operators into Eval.Operator.operator table
- changes external function implementation
This commit is contained in:
백현웅 2022-02-19 21:46:48 +09:00
parent dbcba252bf
commit 71bc70d3bc

170
eval.ml
View file

@ -100,57 +100,37 @@ module Operator = struct
let to_string = Ast.op_to_string
let negate = function
| Int n -> Int ~-n
| Float n -> Float ~-.n
| [Int n] -> Int ~-n
| [Float n] -> Float ~-.n
| _ -> failwith "Operator.negate"
let vi f a b =
match a, b with
| Int a, Int b -> Int (f a b)
let vi f = function
| [Int a; Int b] -> Int (f a b)
| _ -> raise @@ Type.Invalid Int
let vf f a b =
match a, b with
| Float a, Float b -> Float (f a b)
let vf f = function
| [Float a; Float b] -> Float (f a b)
| _ -> raise @@ Type.Expected Float
let vb intf floatf a b =
match a, b with
| Int a, Int b -> Bool (intf a b)
| Float a, Float b -> Bool (floatf a b)
| _ -> raise @@ Type.Expected Bool
let vnot = function
| Bool b -> Bool (not b)
| _ -> raise @@ Type.Expected Bool
let map ?intf ?floatf ?boolf v =
let app x f = f x in
match v with
| Int i -> Option.map (app i) intf
| Float f -> Option.map (app f) floatf
| Bool b -> Option.map (app b) boolf
| _ -> invalid_arg "Operator.map"
let eq = vb Int.equal Float.equal
let neq a b = vnot @@ eq a b
let compare a b =
match a, b with
| Int a, Int b -> Int.compare a b
| Float a, Float b -> Float.compare a b
let compare = function
| [Int a; Int b] -> Int.compare a b
| [Float a; Float b] -> Float.compare a b
| [Bool a; Bool b] -> Bool.compare a b
| [String a; String b] -> String.compare a b
| [Symbol a; Symbol b] -> String.compare a b
| _ -> invalid_arg "Operator.compare"
let ge a b = Bool (compare a b >= 0)
let le a b = Bool (compare a b <= 0)
let gt a b = Bool (compare a b > 0)
let lt a b = Bool (compare a b < 0)
let eq vs = Bool (compare vs = 0)
let neq vs = Bool (compare vs <> 0)
let ge vs = Bool (compare vs >= 0)
let le vs = Bool (compare vs <= 0)
let gt vs = Bool (compare vs > 0)
let lt vs = Bool (compare vs < 0)
(* operator table *)
(* TODO: refactor operator finding alg (support type vars) *)
let operators =
let open Type in
let ip = Int, Int and fp = Float, Float in
let ip = [Int; Int] and fp = [Float; Float] in
let any f = [ip, f; fp, f] in
[
Add, [ip, vi Int.add; fp, vf Float.add];
@ -165,22 +145,13 @@ module Operator = struct
LE, any le;
GT, any gt;
LT, any lt;
Negate, [[Int], negate; [Float], negate];
]
|> List.to_seq
|> Hashtbl.of_seq
let get_types op =
match Hashtbl.find_opt operators op with
| None -> raise @@ Unavailable op
| Some p -> List.map fst p
let get_unary = function
| Negate -> negate
| op -> raise @@ Unavailable op
let get_binary op typ =
let get op =
Hashtbl.find operators op
|> List.assoc_opt typ
end
module External = struct
@ -193,60 +164,58 @@ module External = struct
d /. 180. *. Float.pi
let floatfun f = function
| Float n -> Float (f n)
| v -> raise @@ Type.Invalid (Value.typeof v)
| [Float n] -> Float (f n)
| [v] -> raise @@ Type.Invalid (Value.typeof v)
| _ -> invalid_arg "External.floatfun"
let apply f args =
match f, args with
| "sin", [n] -> floatfun Float.sin n
| "cos", [n] -> floatfun Float.cos n
| "tan", [n] -> floatfun Float.tan n
| "deg", [n] -> floatfun deg n
| "rad", [n] -> floatfun rad n
let f = match f with
| "sin" -> floatfun Float.sin
| "cos" -> floatfun Float.cos
| "tan" -> floatfun Float.tan
| "deg" -> floatfun deg
| "rad" -> floatfun rad
| _ -> raise @@ Invalid f
in
f args
end
let assert_same_length vars args =
let vl = List.length vars
and al = List.length args in
if vl > al then
failwith "assert_same_length"
else if vl < al then
raise Too_many_arguments
let resolve_type op tp =
let optypes = Operator.get_types op in
let q = Queue.create () in
let rec aux (t1, t2) =
if List.mem (t1, t2) optypes then
t1, t2
else begin
[ Type.supertype t1 |> Option.map (fun t1 -> t1, t2);
Type.supertype t2 |> Option.map (fun t2 -> t1, t2); ]
|> List.filter_map Fun.id
|> List.iter (Fun.flip Queue.push q);
aux @@ Queue.pop q
end
let find_operator op ts =
let filter t =
List.filter (fun (ts, _) ->
match ts with [] -> false | x::_ -> t=x)
in
aux tp
let rec aux ops = function
| [] -> List.nth_opt ops 0
| t::ts ->
(match aux (filter t ops) ts with
| None -> Option.bind (Type.supertype t) (fun t -> aux ops (t::ts))
| Some _ as x -> x)
in
aux (Operator.get op) ts
let rec binop op l r =
let promote_values =
let rec promote_until t v =
if Value.typeof v = t
then v
else promote_until t @@ Value.promote v
in
List.map2 promote_until
let unary op v =
match find_operator op [Value.typeof v] with
| None -> raise No_operation
| Some (ts, f) ->
let vs = promote_values ts [v] in
f vs
let binop op l r =
let open Value in
let t1 = typeof l and t2 = typeof r in
let t1, t2 = resolve_type op (t1, t2) in
let rec promote_until t x =
if typeof x = t
then x
else promote_until t (promote x)
in
let l = promote_until t1 l
and r = promote_until t2 r in
match Operator.get_binary op (t1, t2) with
| None -> begin
try binop op (promote l) (promote r)
with _ -> raise No_operation
end
| Some f -> f l r
match find_operator op [typeof l; typeof r] with
| None -> raise No_operation
| Some (ts, f) ->
let vs = promote_values ts [l; r] in
f vs
exception Unbound of string
@ -270,13 +239,8 @@ let rec eval env ast =
let env = Env.bind (v, aux e) env in
eval env f
| Unary (op, t) ->
let t = aux t in
let op = Operator.get_unary op in
op t
| Binop (l, op, r) ->
let l = aux l and r = aux r in
binop op l r
| Unary (op, v) -> unary op (aux v)
| Binop (l, op, r) -> binop op (aux l) (aux r)
| If (co, th, el) ->
begin match aux co with
| Bool true -> aux th