New convenience functions in seq.el

Functions to access the first or all but the first elements of
sequences have been repeatedly asked for (the last occurrence being
https://github.com/NicolasPetton/seq.el/issues/9).

* lisp/emacs-lisp/seq.el (seq-first, seq-rest): New functions.
* test/lisp/emacs-lisp/seq-tests.el (test-seq-first, test-seq-rest):
New tests for seq-first and seq-rest.

1 files changed, 12 insertions, 0 deletions

diff --git a/test/lisp/emacs-lisp/seq-tests.el b/test/lisp/emacs-lisp/seq-tests.el
index 989ec3cf9e0..0f11bd9714c 100644
--- a/test/lisp/emacs-lisp/seq-tests.el
+++ b/test/lisp/emacs-lisp/seq-tests.el
@@ -424,5 +424,17 @@ Evaluate BODY for each created sequence.
     (should (eq (seq-into vec 'vector) vec))
     (should (eq (seq-into str 'string) str))))
 
+(ert-deftest test-seq-first ()
+  (let ((lst '(1 2 3))
+        (vec [1 2 3]))
+    (should (eq (seq-first lst) 1))
+    (should (eq (seq-first vec) 1))))
+
+(ert-deftest test-seq-rest ()
+  (let ((lst '(1 2 3))
+        (vec [1 2 3]))
+    (should (equal (seq-rest lst) '(2 3)))
+    (should (equal (seq-rest vec) [2 3]))))
+
 (provide 'seq-tests)
 ;;; seq-tests.el ends here