ce/eval.ml
2022-01-18 16:52:33 +09:00

37 lines
838 B
OCaml

open Ast
open Ast.Value
exception No_operation
let rec binop op l r =
let tl = typeof l and tr = typeof r in
let ty = Type.merge tl tr in
let rec promote_until t x =
if typeof x = t
then x
else promote_until t (promote x)
in
let l = promote_until ty l
and r = promote_until ty r in
match Binop.get op ty with
| None -> begin
try binop op (promote l) (promote r)
with _ -> raise No_operation
end
| Some f -> f l r
let rec eval = function
| Value v -> v
| Binop (l, op, r) ->
let l = eval l and r = eval r in
binop op l r
| Set_binop_pre (op, l) ->
let l =
match eval l with
| Int n -> n
| v -> raise @@ Invalid_type (typeof v)
in
Hashtbl.replace Parser.precedence op l;
Nop
| Get_binop_pre op ->
Int (Hashtbl.find Parser.precedence op)