Function: 1-

1- is a function defined in data.c.

Signature

(1- NUMBER)

Documentation

Return NUMBER minus one. NUMBER may be a number or a marker.

Markers are converted to integers.

Other relevant functions are documented in the number group.

Shortdoc

;; number
(1- 4)
    => 3

Source Code

// Defined in /usr/src/emacs/src/data.c
{
  number = check_number_coerce_marker (number);

  if (FIXNUMP (number))
    return make_int (XFIXNUM (number) - 1);
  if (FLOATP (number))
    return (make_float (-1.0 + XFLOAT_DATA (number)));
  mpz_sub_ui (mpz[0], *xbignum_val (number), 1);
  return make_integer_mpz ();
}