-DEFUN ("delete-backward-char", Fdelete_backward_char, Sdelete_backward_char,
- 1, 2, "p\nP",
- doc: /* Delete the previous N characters (following if N is negative).
-Optional second arg KILLFLAG non-nil means kill instead (save in kill ring).
-Interactively, N is the prefix arg, and KILLFLAG is set if
-N was explicitly specified. */)
- (n, killflag)
- Lisp_Object n, killflag;
-{
- Lisp_Object value;
- int deleted_special = 0;
- int pos, pos_byte, i;
-
- CHECK_NUMBER (n);
-
- /* See if we are about to delete a tab or newline backwards. */
- pos = PT;
- pos_byte = PT_BYTE;
- for (i = 0; i < XINT (n) && pos_byte > BEGV_BYTE; i++)
- {
- int c;
-
- DEC_BOTH (pos, pos_byte);
- c = FETCH_BYTE (pos_byte);
- if (c == '\t' || c == '\n')
- {
- deleted_special = 1;
- break;
- }
- }
-
- /* In overwrite mode, back over columns while clearing them out,
- unless at end of line. */
- if (XINT (n) > 0
- && ! NILP (current_buffer->overwrite_mode)
- && ! deleted_special
- && ! (PT == ZV || FETCH_BYTE (PT_BYTE) == '\n'))
- {
- int column = (int) current_column (); /* iftc */
-
- value = Fdelete_char (make_number (-XINT (n)), killflag);
- i = column - (int) current_column (); /* iftc */
- Finsert_char (make_number (' '), make_number (i), Qnil);
- /* Whitespace chars are ASCII chars, so we can simply subtract. */
- SET_PT_BOTH (PT - i, PT_BYTE - i);
- }
- else
- value = Fdelete_char (make_number (-XINT (n)), killflag);
-
- return value;
-}