Add bottom & top instances for numbers

src/Neon/Types/HasBottom.purs

@@ -4,7 +4,9 @@ module Neon.Types.HasBottom
   ) where
 
 import Neon.Primitives.Function (constant)
+import Neon.Primitives.Number (infinity)
 import Neon.Types.HasCompare (HasCompare)
+import Neon.Types.HasSubtract (negate)
 import Neon.Values.Ordering (Ordering(LessThan))
 
 foreign import nativeBottomChar :: Char
@@ -27,5 +29,8 @@ instance functionHasBottom :: (HasBottom b) => HasBottom (a -> b) where
 instance intHasBottom :: HasBottom Int where
   bottom = nativeBottomInt
 
+instance numberHasBottom :: HasBottom Number where
+  bottom = negate infinity
+
 instance orderingHasBottom :: HasBottom Ordering where
   bottom = LessThan

src/Neon/Types/HasTop.purs

@@ -4,6 +4,7 @@ module Neon.Types.HasTop
   ) where
 
 import Neon.Primitives.Function (constant)
+import Neon.Primitives.Number (infinity)
 import Neon.Types.HasCompare (HasCompare)
 import Neon.Values.Ordering (Ordering(GreaterThan))
 
@@ -27,5 +28,8 @@ instance functionHasTop :: (HasTop b) => HasTop (a -> b) where
 instance intHasTop :: HasTop Int where
   top = nativeTopInt
 
+instance numberHasTop :: HasTop Number where
+  top = infinity
+
 instance orderingHasTop :: HasTop Ordering where
   top = GreaterThan

test/Neon/Types/HasBottom.purs

@@ -11,4 +11,5 @@ testHasBottom = do
   -- bottom ==> '\0' -- NOTE: purescript/purescript#1602
   bottom unit ==> false
   bottom ==> 0 - 2147483648 -- NOTE: purescript/purescript#1591
+  bottom ==> negate infinity
   bottom ==> LessThan

test/Neon/Types/HasTop.purs

@@ -11,4 +11,5 @@ testHasTop = do
   top ==> '\65535'
   top unit ==> true
   top ==> 2147483647
+  top ==> infinity
   top ==> GreaterThan