1 files changed, 33 insertions, 0 deletions
diff --git a/stdlib/source/lux/control/applicative.lux b/stdlib/source/lux/control/applicative.lux
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+++ b/stdlib/source/lux/control/applicative.lux
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+##  Copyright (c) Eduardo Julian. All rights reserved.
+##  This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
+##  If a copy of the MPL was not distributed with this file,
+##  You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(;module:
+  lux
+  (.. ["F" functor]))
+
+(sig: #export (Applicative f)
+  (: (F;Functor f)
+     functor)
+  (: (All [a]
+       (-> a (f a)))
+     wrap)
+  (: (All [a b]
+       (-> (f (-> a b)) (f a) (f b)))
+     apply))
+
+(def: #export (compA Applicative<F> Applicative<G>)
+  (All [F G] (-> (Applicative F) (Applicative G) (Applicative (All [a] (F (G a))))))
+  (struct (def: functor (F;compF (get@ #functor Applicative<F>)
+                                 (get@ #functor Applicative<G>)))
+          (def: wrap
+            (|>. (:: Applicative<G> wrap) (:: Applicative<F> wrap)))
+          (def: (apply fgf fgx)
+            (let [applyF (:: Applicative<F> apply)
+                  applyG (:: Applicative<G> apply)]
+              ($_ applyF
+                  (:: Applicative<F> wrap applyG)
+                  fgf
+                  fgx)))
+          ))