Alias `-zip-pair`, prepare for breaking change

See issue #135

README.md

@@ -25,6 +25,13 @@ To get function combinators:
 
     ;; Package-Requires: ((dash "2.12.0") (dash-functional "1.2.0") (emacs "24"))
 
+## Upcoming breaking change!
+
+- For backward compatibility reasons `-zip` return a cons-cell instead of a list
+  with two elements when called on two lists. This is a clunky API, and in an
+  upcoming 2.0 release of Dash it will always return a list. If you rely on the
+  cons-cell return value, use `-zip-pair` instead.
+
 ## Syntax highlighting of dash functions
 
 Font lock of dash functions in emacs lisp buffers is now optional.
@@ -1436,6 +1443,9 @@ groupings are equal to the length of the shortest input list.
 If two lists are provided as arguments, return the groupings as a list
 of cons cells. Otherwise, return the groupings as a list of lists.
 
+Please note! This distinction is being removed in an upcoming 2.0
+release of Dash. If you rely on this behavior, use -zip-pair instead.
+
 ```el
 (-zip '(1 2 3) '(4 5 6)) ;; => '((1 . 4) (2 . 5) (3 . 6))
 (-zip '(1 2 3) '(4 5 6 7)) ;; => '((1 . 4) (2 . 5) (3 . 6))

dash.el

@@ -1009,7 +1009,10 @@ second elements of each list, and so on. The lengths of the returned
 groupings are equal to the length of the shortest input list.
 
 If two lists are provided as arguments, return the groupings as a list
-of cons cells. Otherwise, return the groupings as a list of lists. "
+of cons cells. Otherwise, return the groupings as a list of lists.
+
+Please note! This distinction is being removed in an upcoming 2.0
+release of Dash. If you rely on this behavior, use -zip-pair instead."
   (let (results)
     (while (-none? 'null lists)
       (setq results (cons (mapcar 'car lists) results))
@@ -1021,6 +1024,8 @@ of cons cells. Otherwise, return the groupings as a list of lists. "
         (--map (cons (car it) (cadr it)) results)
       results)))
 
+(defalias '-zip-pair '-zip)
+
 (defun -zip-fill (fill-value &rest lists)
   "Zip LISTS, with FILL-VALUE padded onto the shorter lists. The
 lengths of the returned groupings are equal to the length of the

readme-template.md

@@ -25,6 +25,13 @@ To get function combinators:
 
     ;; Package-Requires: ((dash "2.12.0") (dash-functional "1.2.0") (emacs "24"))
 
+## Upcoming breaking change!
+
+- For backward compatibility reasons `-zip` return a cons-cell instead of a list
+  with two elements when called on two lists. This is a clunky API, and in an
+  upcoming 2.0 release of Dash it will always return a list. If you rely on the
+  cons-cell return value, use `-zip-pair` instead.
+
 ## Syntax highlighting of dash functions
 
 Font lock of dash functions in emacs lisp buffers is now optional.