rem: line_start, column_start, line_end, column_end);
add: start_line, start_column, end_line, end_column);
context: void sn_highlight(enum sn_highlights type,    long start_line, int start_column,    long end_line, int end_column){  char * tag;  assert(highlight);  assert(highlightfp);  switch (type) {    case SN_HIGH_COMMENT:      tag = "rem";      break;    case SN_HIGH_STRING:      tag = "str";      break;    default:      sn_error("Unknown highlight type %d\n", type);      sn_panic();  }  fprintf(highlightfp, "%d %s %d.%d %d.%d\n",    highlight_number++, /* Ignored by Sn_Highlight_Text */    tag,    line_start, column_start, line_end, column_end);}