int first_line; /* 1-based line number, or 0 if none. */
int last_line; /* 1-based exclusive last line (0=none). */
int first_column; /* 1-based first column, or 0 if none. */
int first_line; /* 1-based line number, or 0 if none. */
int last_line; /* 1-based exclusive last line (0=none). */
int first_column; /* 1-based first column, or 0 if none. */