open Lexing
open Types
open Util

let get_loc lexbuf =
    Util.loc_from_lexpos lexbuf.lex_curr_p lexbuf.lex_curr_p

let shift_loc (fname, ystart, yend, xstart, xend) yshift xshift =
    (fname, ystart + yshift, yend + yshift, xstart + xshift, xend + xshift)

let shift_back lexbuf = shift_loc (get_loc lexbuf) 0 (-1)

let parse_with_error lexbuf =
    try Some (Parser.program Lexer.token lexbuf) with
    | Lexer.SyntaxError msg ->
        raise (LocError ((shift_back lexbuf), msg))
    | Parser.Error ->
        raise (LocError ((shift_back lexbuf), "syntax error"))

let phase input =
    log_line 2 "- Parse input";
    match input with
    | FileContent (display_name, content) ->
        let lexbuf = Lexing.from_string content in
        lexbuf.lex_curr_p <- { lexbuf.lex_curr_p with pos_fname = display_name };
        let ast = parse_with_error lexbuf in
        (match ast with
            | None -> raise (CompileError "no syntax tree was constructed")
            | Some node -> Ast node)
    | _ -> raise (InvalidInput "parse")