From 4d3bc29f8172ceb9fb5bfb98d6ad800d6b919ce5 Mon Sep 17 00:00:00 2001
From: Sanchayan Maity <maitysanchayan@gmail.com>
Date: Sun, 22 Mar 2020 19:44:17 +0530
Subject: [PATCH] Add comments showing CPS and store lens idea

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
---
 src/Lets/OpticPolyLens.hs | 18 ++++++++++++++++++
 src/Lets/StoreLens.hs     | 11 +++++++++++
 2 files changed, 29 insertions(+)

diff --git a/src/Lets/OpticPolyLens.hs b/src/Lets/OpticPolyLens.hs
index 43698a2..520cb75 100644
--- a/src/Lets/OpticPolyLens.hs
+++ b/src/Lets/OpticPolyLens.hs
@@ -64,6 +64,24 @@ data Lens s t a b =
   Lens
     (forall f. Functor f => (a -> f b) -> s -> f t)
 
+-- Lens s t a b
+
+-- Lens u w s t
+--   (s -> f t) -> w -> f w
+
+-- Lens u w s t . Lens s t a b
+
+-- p :: (->)
+-- p a b
+
+-- f :: s -> a
+-- fcps :: forall r . (a -> r) -> s -> r
+-- f ~ fcps id
+-- fcps = \c -> c . f
+--              (a -> r) . s -> a
+-- forall r . (a -> f r) -> s -> f r
+-- forall f . Functor f => (a -> f b) -> s -> f t
+
 -- Const :: forall b . a -> Const a b
 get ::
   Lens s t a b
diff --git a/src/Lets/StoreLens.hs b/src/Lets/StoreLens.hs
index 4b6e38c..7cc7153 100644
--- a/src/Lets/StoreLens.hs
+++ b/src/Lets/StoreLens.hs
@@ -100,6 +100,17 @@ extractS = \(Store sToa s) -> sToa s
 
 ----
 
+-- data Lens a b =
+--   Lens
+--     (a -> b -> a)
+--     (a -> b)
+-- data Store s a = Store (s -> a) s
+
+-- a -> Store b a
+-- a -> Store (b -> a) b
+-- Drop the Store wrapper
+-- a -> b -> a
+-- a -> b
 data Lens a b =
   Lens
     (a -> Store b a)