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fixed parser bug by filtering out all comments

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This commit is contained in:
Moritz Gmeiner 2024-08-25 03:07:18 +02:00
commit b4e25ee561
3 changed files with 23 additions and 14 deletions
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33
lib/parser.ml
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@ -8,18 +8,10 @@ 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; errors_rev : parser_error list }
type state = { tokens : token list }
let is_at_end state = (List.hd !state.tokens).token_type == Eof
let append_error msg pos state =
let e = ParserError.make pos msg in
{ state with errors_rev = e :: state.errors_rev }
let advance state = state := { !state with tokens = List.tl !state.tokens }
let peek state = List.hd !state.tokens
let peek_tt (state : state ref) : token_type = (peek state).token_type
let cur_pos state = (peek state).pos
let advance state = state := { tokens = List.tl !state.tokens }
let next state =
assert (not ((List.hd !state.tokens).token_type == Eof));
@ -27,6 +19,10 @@ let next state =
advance state;
token
let peek state = List.hd !state.tokens
let peek_tt (state : state ref) : token_type = (peek state).token_type
let cur_pos state = (peek state).pos
let advance_if state tt =
if peek_tt state == tt then (
advance state;
@ -187,6 +183,7 @@ let statement (state : state ref) : stmt_result =
let stmt = make_print pos expr in
Ok stmt
| tt ->
advance state;
let msg =
Printf.sprintf "Statement stating with %s not yet implemented" (show_token_type tt)
in
@ -200,17 +197,25 @@ let rec synchronise (state : state ref) =
advance state;
synchronise state
let rec parse (tokens : token list) : parse_result =
let state = ref { tokens; errors_rev = [] } in
let rec parse_impl (state : state ref) : parse_result =
let result = statement state in
match result with
| Ok stmt when peek_tt state == Eof -> Ok [ stmt ]
| Ok stmt ->
let* stmts = parse !state.tokens in
print_endline (show_stmt stmt.stmt);
let* stmts = parse_impl state in
Ok (stmt :: stmts)
| Error e -> (
synchronise state;
if peek_tt state == Eof then Error [ e ]
else
let tail_result = parse !state.tokens in
let tail_result = parse_impl state in
match tail_result with Ok _ -> Error [ e ] | Error es -> Error (e :: es))
let parse (tokens : token list) : parse_result =
(* filter out all the comment tokens *)
let tokens =
List.filter (fun tok -> match tok.token_type with Comment _ -> false | _ -> true) tokens
in
let state = ref { tokens } in
parse_impl state