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implemented break

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This commit is contained in:
Moritz Gmeiner 2024-08-27 02:46:17 +02:00
commit e288a626fd
6 changed files with 84 additions and 72 deletions
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36
lib/parser.ml
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@ -8,10 +8,18 @@ open Stmt
type parse_result = (stmt_node list, parser_error list) result
type stmt_result = (stmt_node, parser_error) result
type expr_result = (expr_node, parser_error) result
type state = { tokens : token list }
type state = { tokens : token list; is_in_loop : bool }
let with_is_in_loop (f : state ref -> stmt_result) (state : state ref) : stmt_result =
let was_in_loop = !state.is_in_loop in
state := { !state with is_in_loop = true };
let result = f state in
state := { !state with is_in_loop = was_in_loop };
result
let make_state tokens = ref { tokens; is_in_loop = false }
let is_at_end state = (List.hd !state.tokens).token_type = Eof
let advance state = state := { tokens = List.tl !state.tokens }
let advance state = state := { !state with tokens = List.tl !state.tokens }
let next state =
assert (not ((List.hd !state.tokens).token_type = Eof));
@ -257,7 +265,12 @@ and while_loop (state : state ref) : stmt_result =
let* _ = consume state LeftParen in
let* cond = expression state in
let* _ = consume state RightParen in
let* body = statement state in
(* let was_in_loop = !state.is_in_loop in
state := { !state with is_in_loop = true };
let body = statement state in
state := { !state with is_in_loop = was_in_loop };
let* body = body in *)
let* body = with_is_in_loop statement state in
make_while pos cond body |> Result.ok
and for_loop (state : state ref) : stmt_result =
@ -287,7 +300,12 @@ and for_loop (state : state ref) : stmt_result =
| _ -> expression state |> Result.map Option.some
in
let* _ = consume state RightParen in
let* body = statement state in
(* let was_in_loop = !state.is_in_loop in
state := { !state with is_in_loop = true };
let body = statement state in
state := { !state with is_in_loop = was_in_loop };
let* body = body in *)
let* body = with_is_in_loop statement state in
let body =
match update with
| Some update ->
@ -311,6 +329,14 @@ and expr_stmt (state : state ref) : stmt_result =
and statement (state : state ref) : stmt_result =
let pos = cur_pos state in
match peek_tt state with
| Break ->
if !state.is_in_loop then (
advance state;
let* _ = consume state Semicolon in
make_break pos |> Result.ok)
else
let msg = "Can use break only in loops" in
ParserError.make pos msg |> Result.error
| Print ->
advance state;
let* expr = expression state in
@ -371,5 +397,5 @@ let parse (tokens : token list) : parse_result =
let tokens =
List.filter (fun tok -> match tok.token_type with Comment _ -> false | _ -> true) tokens
in
let state = ref { tokens } in
let state = make_state tokens in
parse_impl state