Add any and all (bug#79611)

* lisp/subr.el (all, any): New.
* test/lisp/subr-tests.el (subr-all, subr-any): New tests.
* doc/lispref/lists.texi (List Elements): Document.
* etc/NEWS: Announce.

4 files changed, 75 insertions, 0 deletions

diff --git a/doc/lispref/lists.texi b/doc/lispref/lists.texi
index da6d167c740..37ef8d46525 100644
--- a/doc/lispref/lists.texi
+++ b/doc/lispref/lists.texi
@@ -415,6 +415,33 @@ will return a list equal to @var{list}.
 @end example
 @end defun
 
+@defun all pred list
+This function returns @code{t} if @var{pred} is true for all elements in
+@var{list}.
+
+@example
+@group
+(all #'numberp '(1 2 3 4))     @result{} t
+(all #'numberp '(1 2 a b 3 4)) @result{} nil
+(all #'numberp '())            @result{} t
+@end group
+@end example
+@end defun
+
+@defun any pred list
+This function returns non-@code{nil} if @var{pred} is true for at least
+one element in @var{list}.  The returned value is the longest @var{list}
+suffix whose first element satisfies @var{pred}.
+
+@example
+@group
+(any #'symbolp '(1 2 3 4))     @result{} nil
+(any #'symbolp '(1 2 a b 3 4)) @result{} (a b 3 4)
+(any #'symbolp '())            @result{} nil
+@end group
+@end example
+@end defun
+
 @defun last list &optional n
 This function returns the last link of @var{list}.  The @code{car} of
 this link is the list's last element.  If @var{list} is null,
diff --git a/etc/NEWS b/etc/NEWS
index cf608578c34..94a01a63649 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -3143,6 +3143,11 @@ signal an error if they are given a non-integer.
 These work like 'drop' and 'take' but use a predicate instead of counting.
 
 +++
+** New functions 'any' and 'all'.
+These return non-nil for lists where any and all elements, respectively,
+satisfy a given predicate.
+
++++
 ** The 'defvar-local' macro second argument is now optional.
 This means that you can now call it with just one argument, like
 'defvar', to declare a variable both special, and buffer-local.
diff --git a/lisp/subr.el b/lisp/subr.el
index 403e9dac376..216ad5eb4ab 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -1176,6 +1176,20 @@ side-effects, and the argument LIST is not modified."
   (while (and list (funcall pred (car list)))
     (setq list (cdr list)))
   list)
+
+(defun all (pred list)
+  "Non-nil if PRED is true for all elements in LIST."
+  (declare (compiler-macro (lambda (_) `(not (drop-while ,pred ,list)))))
+  (not (drop-while pred list)))
+
+(defun any (pred list)
+  "Non-nil if PRED is true for at least one element in LIST.
+Returns the LIST suffix starting at the first element that satisfies PRED,
+or nil if none does."
+  (declare (compiler-macro
+            (lambda (_)
+              `(drop-while (lambda (x) (not (funcall ,pred x))) ,list))))
+  (drop-while (lambda (x) (not (funcall pred x))) list))
 
 ;;;; Keymap support.
 
diff --git a/test/lisp/subr-tests.el b/test/lisp/subr-tests.el
index ae5932d96b3..fc980eae596 100644
--- a/test/lisp/subr-tests.el
+++ b/test/lisp/subr-tests.el
@@ -1545,5 +1545,34 @@ final or penultimate step during initialization."))
     (should (equal (funcall (subr--identity #'take-while) #'plusp ls)
                    '(3 2 1)))))
 
+(ert-deftest subr-all ()
+  (should (equal (all #'hash-table-p nil) t))
+  (let ((ls (append '(3 2 1) '(0) '(-1 -2 -3))))
+    (should (equal (all #'numberp ls) t))
+    (should (equal (all (lambda (x) (numberp x)) ls) t))
+    (should (equal (all #'plusp ls) nil))
+    (should (equal (all #'bufferp ls) nil))
+    (let ((z 9))
+      (should (equal (all (lambda (x) (< x z)) ls) t))
+      (should (equal (all (lambda (x) (> x (- z 9))) ls) nil))
+      (should (equal (all (lambda (x) (> x z)) ls) nil)))
+    (should (equal (funcall (subr--identity #'all) #'plusp ls) nil))
+    (should (equal (funcall (subr--identity #'all) #'numberp ls) t))))
+
+(ert-deftest subr-any ()
+  (should (equal (any #'hash-table-p nil) nil))
+  (let ((ls (append '(3 2 1) '(0) '(-1 -2 -3))))
+    (should (equal (any #'numberp ls) ls))
+    (should (equal (any (lambda (x) (numberp x)) ls) ls))
+    (should (equal (any #'plusp ls) ls))
+    (should (equal (any #'zerop ls) '(0 -1 -2 -3)))
+    (should (equal (any #'bufferp ls) nil))
+    (let ((z 9))
+      (should (equal (any (lambda (x) (< x z)) ls) ls))
+      (should (equal (any (lambda (x) (< x (- z 9))) ls) '(-1 -2 -3)))
+      (should (equal (any (lambda (x) (> x z)) ls) nil)))
+    (should (equal (funcall (subr--identity #'any) #'minusp ls) '(-1 -2 -3)))
+    (should (equal (funcall (subr--identity #'any) #'stringp ls) nil))))
+
 (provide 'subr-tests)
 ;;; subr-tests.el ends here