[ooc-compiler] Position of runtime error

[August K. <fus...@co...>]

Hello all,

In runtime error messages, OOC outputs the position where the error 
occurred but no info on line (or column) number, for instance:

##
## Runtime error in module Test at pos 171
## Dereference of NIL
##

It's kind of hard to find the position in an editor that lacks Emacs' 
`goto-char' function and even for Emacs users it would be more 
convenient with a line (and a column) number.

If the function _runtime_error in lib/src/RT0.c made a call to the 
function GetLineAndColumn below the error message could be output as for 
instance:

##
## Runtime error in module Test at pos 171 (line 11, column 3)
## Dereference of NIL
##

Comments?


Regards,
August


(I suspect that there may be some library function somewhere that does 
the same thing as GetLineAndColumn)

/*
  * GetLineAndColumn(f, p, &ln, &c) calculates line number ln and
  * column number c corresponding to position p in file f .
  *
  * precondition: p > 0
  *
  * postcondition: ln > 0 and c >= 0
  */

static void GetLineAndColumn(const char *filename, int pos,
                              /*@out@*/ int *line, /*@out@*/ int *column)
{
    FILE *f;
    int i, c, ret;

    assert(pos > 0);
    f = fopen(filename, "r");
    if (f == NULL) { perror(__func__); exit(EXIT_FAILURE); }
    *line = 1;
    *column = 0;
    for (i = 1; i < pos; i++) {
       c = fgetc(f);
       if (ferror(f)) {
          perror(__func__); exit(EXIT_FAILURE);
       } else if (feof(f)) {
          fprintf(stderr, "%s: Reached end of file\n", __func__);
          exit(EXIT_FAILURE);
       } else if (c == '\n') {
          (*line)++; *column = 0;
       } else {
          (*column)++;
       }
    }
    ret = fclose(f);
    if (ret == EOF) { perror(__func__); exit(EXIT_FAILURE); }
    assert((*line > 0) && (*column >= 0));
}