Improve the semantic of seq-some

Update seq-some to return non-nil if the predicate returns non-nil for
any element of the seq, in which case the returned value is the one
returned by the predicate.

* lisp/emacs-lisp/seq.el (seq-some): Update the function and its
  docstring.
* test/automated/seq-tests.el (test-seq-some): Add a regression test.
* doc/lispref/sequences.texi (Sequence Functions): Update the
  documentation for seq-some.

1 files changed, 7 insertions, 5 deletions

diff --git a/lisp/emacs-lisp/seq.el b/lisp/emacs-lisp/seq.el
index bf5495baac3..8dc91471312 100644
--- a/lisp/emacs-lisp/seq.el
+++ b/lisp/emacs-lisp/seq.el
@@ -261,11 +261,13 @@ If SEQ is empty, return INITIAL-VALUE and FUNCTION is not called."
     t))
 
 (cl-defgeneric seq-some (pred seq)
-  "Return any element for which (PRED element) is non-nil in SEQ, nil otherwise."
+  "Return non-nil if (PRED element) is non-nil for any element in SEQ, nil otherwise.
+If so, return the non-nil value returned by PRED."
   (catch 'seq--break
     (seq-doseq (elt seq)
-      (when (funcall pred elt)
-        (throw 'seq--break elt)))
+      (let ((result (funcall pred elt)))
+        (when result
+          (throw 'seq--break result))))
     nil))
 
 (cl-defgeneric seq-count (pred seq)
@@ -280,8 +282,8 @@ If SEQ is empty, return INITIAL-VALUE and FUNCTION is not called."
   "Return the first element in SEQ that equals to ELT.
 Equality is defined by TESTFN if non-nil or by `equal' if nil."
   (seq-some (lambda (e)
-                (funcall (or testfn #'equal) elt e))
-              seq))
+              (funcall (or testfn #'equal) elt e))
+            seq))
 
 (cl-defgeneric seq-uniq (seq &optional testfn)
   "Return a list of the elements of SEQ with duplicates removed.