[LensTest]

src/LensTest.purs

+module LensTest where
+
+import Prelude
+import Data.Generic.Rep (class Generic)
+import Data.Generic.Rep.Show (genericShow)
+import Data.Lens
+import Effect
+import Effect.Console
+
+newtype S =
+  S {
+    first :: String
+  , last :: String
+  }
+derive instance genericS :: Generic S _
+instance showS :: Show S where
+  show = genericShow
+
+defaultS :: S
+defaultS =
+  S {
+    first: "First"
+  , last: "Last"
+  }
+
+newtype T =
+  T {
+    s :: S
+  }
+
+derive instance genericT :: Generic T _
+instance showT :: Show T where
+  show = genericShow
+
+defaultT :: T
+defaultT =
+  T {
+    s: defaultS
+  }
+
+_s :: Lens' T S
+_s = lens getter setter
+  where
+    getter (T {s}) = s
+    setter (T t) s = T $ t { s = s }
+
+_last :: Lens' S String
+_last = lens getter setter
+  where
+    getter (S {last}) = last
+    setter (S s) l = S $ s { last = l }
+
+
+func :: T -> Lens' T String -> Effect Unit
+func t l = do
+  logShow $ view l t
+  logShow $ set l "last" t
+
+-- funcT :: T -> Effect Unit
+-- funcT t = func t (_ s <<< _last)