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Dmitry Boulytchev 2018-04-02 10:38:54 +03:00
parent 7352dc3da8
commit b4f6f48e30
1 changed files with 21 additions and 13 deletions
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34
src/Language.ml
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@ -162,20 +162,27 @@ module Stmt =
Takes an environment, a configuration and a statement, and returns another configuration. The
environment is the same as for expressions
*)
let rec eval env ((st, i, o) as conf) stmt =
let rec eval env ((st, i, o) as conf) k stmt =
let seq x y =
match x, y with
| Skip, _ -> y
| _, Skip -> x
| _ -> Seq (x, y)
in
match stmt with
| Read x -> (match i with z::i' -> (State.update x z st, i', o) | _ -> failwith "Unexpected end of input")
| Write e -> let v, (st, i, o) = Expr.eval env conf e in (st, i, o @ [v])
| Assign (x, e) -> let v, (st, i, o) = Expr.eval env conf e in (State.update x v st, i, o)
| Seq (s1, s2) -> eval env (eval env conf s1) s2
| Skip -> conf
| If (e, s1, s2) -> let v, conf = Expr.eval env conf e in eval env conf (if v <> 0 then s1 else s2)
| While (e, s) -> let v, conf = Expr.eval env conf e in if v = 0 then conf else eval env (eval env conf s) stmt
| Repeat (s, e) -> let conf = eval env conf s in
let v, conf' = Expr.eval env conf e in
if v = 0 then eval env conf' stmt else conf
| Read x -> eval env (match i with z::i' -> (State.update x z st, i', o) | _ -> failwith "Unexpected end of input") Skip k
| Write e -> eval env (let v, (st, i, o) = Expr.eval env conf e in (st, i, o @ [v])) Skip k
| Assign (x, e) -> eval env (let v, (st, i, o) = Expr.eval env conf e in (State.update x v st, i, o)) Skip k
| Seq (s1, s2) -> eval env conf (seq s2 k) s1
| Skip -> (match k with Skip -> conf | _ -> eval env conf Skip k)
| If (e, s1, s2) -> let v, conf = Expr.eval env conf e in eval env conf k (if v <> 0 then s1 else s2)
| While (e, s) -> let v, conf = Expr.eval env conf e in
if v = 0
then eval env conf Skip k
else eval env conf (seq stmt k) s
| Repeat (s, e) -> eval env conf (seq (While (Expr.Binop ("==", e, Expr.Const 0), s)) k) s
| Return e -> failwith "Not implemented"
| Call (f, args) -> snd (Expr.eval env conf (Expr.Call (f, args)))
| Call (f, args) -> eval env (snd (Expr.eval env conf (Expr.Call (f, args)))) k Skip
(* Statement parser *)
ostap (
@ -250,10 +257,11 @@ let eval (defs, body) i =
method definition env f args (st, i, o) =
let xs, locs, s = snd @@ M.find f m in
let st' = List.fold_left (fun st (x, a) -> State.update x a st) (State.enter st (xs @ locs)) (List.combine xs args) in
let st'', i', o' = Stmt.eval env (st', i, o) s in
let st'', i', o' = Stmt.eval env (st', i, o) Skip s in
0, (State.leave st'' st, i', o')
end)
(State.empty, i, [])
Skip
body
in
o