- Small additions.

2 files changed, 26 insertions, 8 deletions

diff --git a/stdlib/source/lux/data/product.lux b/stdlib/source/lux/data/product.lux
index 712e96437..09915b11e 100644
--- a/stdlib/source/lux/data/product.lux
+++ b/stdlib/source/lux/data/product.lux
@@ -1,4 +1,5 @@
-(.module: {#.doc "Functionality for working with tuples (particularly 2-tuples)."}
+(.module:
+  {#.doc "Functionality for working with tuples (particularly 2-tuples)."}
   lux)
 
 ## [Functions]
@@ -36,3 +37,10 @@
         (-> [a b] [c d])))
   (function [[x y]]
     [(f x) (g y)]))
+
+(def: #export (fork f g)
+  (All [a l r]
+    (-> (-> a l) (-> a r)
+        (-> a [l r])))
+  (function [x]
+    [(f x) (g x)]))
diff --git a/stdlib/source/lux/data/sum.lux b/stdlib/source/lux/data/sum.lux
index c2373c238..1a58127c1 100644
--- a/stdlib/source/lux/data/sum.lux
+++ b/stdlib/source/lux/data/sum.lux
@@ -1,7 +1,7 @@
-(.module: {#.doc "Functionality for working with variants (particularly 2-variants)."}
+(.module:
+  {#.doc "Functionality for working with variants (particularly 2-variants)."}
   lux)
 
-## [Values]
 (do-template [<name> <type> <index>]
   [(def: #export (<name> value)
      (All [a b] (-> <type> (| a b)))
@@ -10,13 +10,23 @@
   [left  a +0]
   [right b +1])
 
-(def: #export (either f g)
-  (All [a b c] (-> (-> a c) (-> b c)
-                   (-> (| a b) c)))
+(def: #export (either fl fr)
+  (All [a b c]
+    (-> (-> a c) (-> b c)
+        (-> (| a b) c)))
   (function [input]
     (case input
-      (+0 l) (f l)
-      (+1 r) (g r))))
+      (+0 l) (fl l)
+      (+1 r) (fr r))))
+
+(def: #export (each fl fr)
+  (All [l l' r r']
+    (-> (-> l l') (-> r r')
+        (-> (| l r) (| l' r'))))
+  (function [input]
+    (case input
+      (+0 l) (+0 (fl l))
+      (+1 r) (+1 (fr r)))))
 
 (do-template [<name> <side> <tag>]
   [(def: #export (<name> es)