diff --git a/doc/lispref/numbers.texi b/doc/lispref/numbers.texi index 3c70d2f0a06..54c8d3e5988 100644 --- a/doc/lispref/numbers.texi +++ b/doc/lispref/numbers.texi @@ -642,10 +642,11 @@ product. When given no arguments, @code{*} returns 1. @end example @end defun -@defun / dividend divisor &rest divisors -This function divides @var{dividend} by @var{divisor} and returns the -quotient. If there are additional arguments @var{divisors}, then it -divides @var{dividend} by each divisor in turn. Each argument may be a +@defun / number &rest divisors +With one or more @var{divisors}, this function divides @var{number} +by each divisor in @var{divisors} in turn, and returns the quotient. +With no @var{divisors}, this function returns 1/@var{number}, i.e., +the multiplicative inverse of @var{number}. Each argument may be a number or a marker. If all the arguments are integers, the result is an integer, obtained @@ -673,6 +674,14 @@ by rounding the quotient towards zero after each division. @result{} 2.5 @end group @group +(/ 4.0) + @result{} 0.25 +@end group +@group +(/ 4) + @result{} 0 +@end group +@group (/ 25 3 2) @result{} 4 @end group diff --git a/etc/NEWS b/etc/NEWS index 7b31357c345..ac6ccb86f01 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -1008,6 +1008,12 @@ dynamically. dynamically. Any third-party code that changes these templates should be updated accordingly. ++++ +** ‘(/ N)’ is now equivalent to ‘(/ 1 N)’ rather than to ‘(/ N 1)’. +The new behavior is compatible with Common Lisp and with XEmacs. +This change does not affect Lisp code intended to be portable to +Emacs 24.2 and earlier, which did not support unary ‘/’. + * Lisp Changes in Emacs 25.1 diff --git a/lisp/color.el b/lisp/color.el index d572222021b..97656ca9e33 100644 --- a/lisp/color.el +++ b/lisp/color.el @@ -93,7 +93,7 @@ resulting list." "Compute hue from V1 and V2 H. Used internally by `color-hsl-to-rgb'." (cond - ((< h (/ 1.0 6)) (+ v1 (* (- v2 v1) h 6.0))) + ((< h (/ 6.0)) (+ v1 (* (- v2 v1) h 6.0))) ((< h 0.5) v2) ((< h (/ 2.0 3)) (+ v1 (* (- v2 v1) (- (/ 2.0 3) h) 6.0))) (t v1))) @@ -110,9 +110,9 @@ inclusive." (- (+ L S) (* L S)))) (m1 (- (* 2.0 L) m2))) (list - (color-hue-to-rgb m1 m2 (mod (+ H (/ 1.0 3)) 1)) + (color-hue-to-rgb m1 m2 (mod (+ H (/ 3.0)) 1)) (color-hue-to-rgb m1 m2 H) - (color-hue-to-rgb m1 m2 (mod (- H (/ 1.0 3)) 1)))))) + (color-hue-to-rgb m1 m2 (mod (- H (/ 3.0)) 1)))))) (defun color-complement-hex (color) "Return the color that is the complement of COLOR, in hexadecimal format." @@ -199,13 +199,13 @@ RED, GREEN and BLUE should be between 0.0 and 1.0, inclusive." (b (+ (* 0.0556434 X) (* -0.2040259 Y) (* 1.0572252 Z)))) (list (if (<= r 0.0031308) (* 12.92 r) - (- (* 1.055 (expt r (/ 1 2.4))) 0.055)) + (- (* 1.055 (expt r (/ 2.4))) 0.055)) (if (<= g 0.0031308) (* 12.92 g) - (- (* 1.055 (expt g (/ 1 2.4))) 0.055)) + (- (* 1.055 (expt g (/ 2.4))) 0.055)) (if (<= b 0.0031308) (* 12.92 b) - (- (* 1.055 (expt b (/ 1 2.4))) 0.055))))) + (- (* 1.055 (expt b (/ 2.4))) 0.055))))) (defconst color-d65-xyz '(0.950455 1.0 1.088753) "D65 white point in CIE XYZ.") @@ -222,13 +222,13 @@ conversion. If omitted or nil, use `color-d65-xyz'." (yr (/ Y Yr)) (zr (/ Z Zr)) (fx (if (> xr color-cie-ε) - (expt xr (/ 1 3.0)) + (expt xr (/ 3.0)) (/ (+ (* color-cie-κ xr) 16) 116.0))) (fy (if (> yr color-cie-ε) - (expt yr (/ 1 3.0)) + (expt yr (/ 3.0)) (/ (+ (* color-cie-κ yr) 16) 116.0))) (fz (if (> zr color-cie-ε) - (expt zr (/ 1 3.0)) + (expt zr (/ 3.0)) (/ (+ (* color-cie-κ zr) 16) 116.0)))) (list (- (* 116 fy) 16) ; L diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el index 6f7ba3353f6..d138effcd9d 100644 --- a/lisp/emacs-lisp/bytecomp.el +++ b/lisp/emacs-lisp/bytecomp.el @@ -3617,8 +3617,8 @@ discarding." (defun byte-compile-quo (form) (let ((len (length form))) - (cond ((<= len 2) - (byte-compile-subr-wrong-args form "2 or more")) + (cond ((< len 2) + (byte-compile-subr-wrong-args form "1 or more")) ((= len 3) (byte-compile-two-args form)) (t diff --git a/lisp/emacs-lisp/cl-extra.el b/lisp/emacs-lisp/cl-extra.el index dddfca7ae83..afa021dffc7 100644 --- a/lisp/emacs-lisp/cl-extra.el +++ b/lisp/emacs-lisp/cl-extra.el @@ -497,7 +497,7 @@ This sets the values of: `cl-most-positive-float', `cl-most-negative-float', (setq cl-least-positive-normalized-float y cl-least-negative-normalized-float (- y)) ;; Divide down until value underflows to zero. - (setq x (/ 1 z) y x) + (setq x (/ z) y x) (while (condition-case _ (> (/ x 2) 0) (arith-error nil)) (setq x (/ x 2))) (setq cl-least-positive-float x diff --git a/lisp/net/shr-color.el b/lisp/net/shr-color.el index 482f829707d..f8d358c27b3 100644 --- a/lisp/net/shr-color.el +++ b/lisp/net/shr-color.el @@ -211,7 +211,7 @@ This will convert \"80 %\" to 204, \"100 %\" to 255 but \"123\" to \"123\"." "Convert X Y H to RGB value." (when (< h 0) (incf h)) (when (> h 1) (decf h)) - (cond ((< h (/ 1 6.0)) (+ x (* (- y x) h 6))) + (cond ((< h (/ 6.0)) (+ x (* (- y x) h 6))) ((< h 0.5) y) ((< h (/ 2.0 3.0)) (+ x (* (- y x) (- (/ 2.0 3.0) h) 6))) (t x))) @@ -223,9 +223,9 @@ This will convert \"80 %\" to 204, \"100 %\" to 255 but \"123\" to \"123\"." (setq m2 (* l (+ s 1))) (setq m2 (- (+ l s) (* l s)))) (setq m1 (- (* l 2) m2)) - (list (shr-color-hue-to-rgb m1 m2 (+ h (/ 1 3.0))) + (list (shr-color-hue-to-rgb m1 m2 (+ h (/ 3.0))) (shr-color-hue-to-rgb m1 m2 h) - (shr-color-hue-to-rgb m1 m2 (- h (/ 1 3.0)))))) + (shr-color-hue-to-rgb m1 m2 (- h (/ 3.0)))))) (defun shr-color->hexadecimal (color) "Convert any color format to hexadecimal representation. diff --git a/src/data.c b/src/data.c index b85d8a77106..33fe2855c99 100644 --- a/src/data.c +++ b/src/data.c @@ -2603,6 +2603,7 @@ arith_driver (enum arithop code, ptrdiff_t nargs, Lisp_Object *args) accum = 0; break; case Amult: + case Adiv: accum = 1; break; case Alogand: @@ -2658,7 +2659,7 @@ arith_driver (enum arithop code, ptrdiff_t nargs, Lisp_Object *args) accum *= next; break; case Adiv: - if (!argnum) + if (! (argnum || nargs == 1)) accum = next; else { @@ -2727,7 +2728,7 @@ float_arith_driver (double accum, ptrdiff_t argnum, enum arithop code, accum *= next; break; case Adiv: - if (!argnum) + if (! (argnum || nargs == 1)) accum = next; else { @@ -2782,9 +2783,11 @@ usage: (* &rest NUMBERS-OR-MARKERS) */) } DEFUN ("/", Fquo, Squo, 1, MANY, 0, - doc: /* Return first argument divided by all the remaining arguments. + doc: /* Divide number by divisors and return the result. +With two or more arguments, return first argument divided by the rest. +With one argument, return 1 divided by the argument. The arguments must be numbers or markers. -usage: (/ DIVIDEND &rest DIVISORS) */) +usage: (/ NUMBER &rest DIVISORS) */) (ptrdiff_t nargs, Lisp_Object *args) { ptrdiff_t argnum;