1 files changed, 76 insertions, 0 deletions
diff --git a/stdlib/source/lux/time/day.lux b/stdlib/source/lux/time/day.lux
new file mode 100644
index 000000000..2288111d7
--- /dev/null
+++ b/stdlib/source/lux/time/day.lux
@@ -0,0 +1,76 @@
+(.module:
+  [lux #*
+   [control
+    [equivalence (#+ Equivalence)]
+    [order (#+ Order)]
+    [enum (#+ Enum)]]])
+
+(type: #export Day
+  #Sunday
+  #Monday
+  #Tuesday
+  #Wednesday
+  #Thursday
+  #Friday
+  #Saturday)
+
+(structure: #export equivalence (Equivalence Day)
+  (def: (= reference sample)
+    (case [reference sample]
+      (^template [<tag>]
+        [<tag> <tag>]
+        #1)
+      ([#Sunday]
+       [#Monday]
+       [#Tuesday]
+       [#Wednesday]
+       [#Thursday]
+       [#Friday]
+       [#Saturday])
+
+      _
+      #0)))
+
+(def: (day-to-nat day)
+  (-> Day Nat)
+  (case day
+    #Sunday    0
+    #Monday    1
+    #Tuesday   2
+    #Wednesday 3
+    #Thursday  4
+    #Friday    5
+    #Saturday  6))
+
+(`` (structure: #export order (Order Day)
+      (def: &equivalence ..equivalence)
+      (~~ (do-template [<name> <comp>]
+            [(def: (<name> reference sample)
+               (<comp> (day-to-nat reference) (day-to-nat sample)))]
+
+            [<  n/<]
+            [<= n/<=]
+            [>  n/>]
+            [>= n/>=]
+            ))))
+
+(structure: #export enum (Enum Day)
+  (def: &order ..order)
+  (def: (succ day)
+    (case day
+      #Sunday    #Monday
+      #Monday    #Tuesday
+      #Tuesday   #Wednesday
+      #Wednesday #Thursday
+      #Thursday  #Friday
+      #Friday    #Saturday
+      #Saturday  #Sunday))
+  (def: (pred day)
+    (case day
+      #Monday    #Sunday
+      #Tuesday   #Monday
+      #Wednesday #Tuesday
+      #Thursday  #Wednesday
+      #Friday    #Thursday
+      #Saturday  #Friday
+      #Sunday    #Saturday)))