51 lines
1.6 KiB
OCaml
51 lines
1.6 KiB
OCaml
open E0
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open E0.Util
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module I = Parser.MenhirInterpreter
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let get_parse_error env =
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match I.stack env with
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| lazy Nil -> "Invalid syntax"
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| lazy (Cons (I.Element (state, _, _, _), _)) ->
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try (E0.Parser_messages.message (I.number state)) with
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| Not_found -> "invalid syntax (no specific message for this eror)"
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let rec parse lexbuf (checkpoint : Ast.program I.checkpoint) =
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match checkpoint with
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| I.InputNeeded _env ->
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let token = Lexer.f lexbuf in
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let startp = lexbuf.lex_start_p
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and endp = lexbuf.lex_curr_p in
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let checkpoint = I.offer checkpoint (token, startp, endp) in
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parse lexbuf checkpoint
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| I.Shifting _
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| I.AboutToReduce _ ->
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let checkpoint = I.resume checkpoint in
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parse lexbuf checkpoint
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| I.HandlingError _env ->
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let line, pos = Util.get_lexing_position lexbuf in
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let err = get_parse_error _env in
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raise (Syntax_error (Some (line, pos), err))
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| I.Accepted v -> v
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| I.Rejected ->
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raise (Syntax_error (None, "invalid syntax (parser rejected the input)"))
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let try_parse lexbuf =
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try
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let program = parse lexbuf (Parser.Incremental.program lexbuf.lex_curr_p) in
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Ok program
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with
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| Util.Syntax_error (pos, err) ->
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begin
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match pos with
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| Some (line, pos) ->
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Error (Printf.sprintf "Syntax error on line %d, character %d: %s" line pos err)
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| None -> Error (Printf.sprintf "Syntax error: %s" err)
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end
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let () =
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let p = Lexing.from_channel stdin |> try_parse in
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match p with
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| Error msg -> Printf.eprintf "Could not load program: %s" msg
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| Ok p -> Ast.show_program p |> print_endline
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