From 8f811cd88ccafd6d7a05e8c5aaaaa78d3bc43444 Mon Sep 17 00:00:00 2001
From: Andrew Cady <d@jerkface.net>
Date: Tue, 5 Jan 2021 13:06:36 -0500
Subject: generalize

---
 shelf.hs | 60 ++++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 42 insertions(+), 18 deletions(-)

diff --git a/shelf.hs b/shelf.hs
index 954cf94..e5b615d 100755
--- a/shelf.hs
+++ b/shelf.hs
@@ -3,6 +3,7 @@
   --ghc-options -Wall --ghc-options -Wno-unused-imports --ghc-options -Wno-name-shadowing -}
 {-# language NoImplicitPrelude #-}
 {-# language DuplicateRecordFields #-}
+{-# language RecordWildCards #-}
 import Rebase.Prelude
 import Control.Lens
 
@@ -30,28 +31,51 @@ formatFeet l = unwords $ toList (feet f) ++ toList (inches i n d)
 
 type Inches = Rational
 
-boardLength, boardThickness, kickerHeight, availableSpace :: Inches
-boardLength = 6 * 12
-boardThickness = 5/8
-kickerHeight = 4 + 1/2
-numHorizontals, numShelves :: Int
-numShelves = length shelves
+data Shelf = Shelf {
+  boardLength :: Inches,
+  boardThickness :: Inches,
+  kickerHeight :: Inches,
+  shelves :: [Integer]
+}
 
-numHorizontals = numShelves + 1
-availableSpace = boardLength - kickerHeight - (toRational numHorizontals) * boardThickness
+bookshelf :: Shelf
+bookshelf = Shelf {
+  boardLength = 6 * 12,
+  boardThickness = 5/8,
+  kickerHeight = 4 + 1/2,
+  shelves = [4, 4, 4, 3, 3]
+}
 
-shelves :: [Inches]
-shelves = map (* availableSpace) $ map (% 18) [4, 4, 4, 3, 3]
+pianoCubbies :: Shelf
+pianoCubbies = Shelf {
+  boardLength = 52 + 1%8,
+  boardThickness = 5/8,
+  kickerHeight = 0,
+  shelves = [1, 1, 1, 1]
+}
 
-positions, positions' :: [Inches]
-positions = map sum $ (tail . inits) $ concatMap (: [boardThickness]) $ kickerHeight : shelves
+positions, positions' :: Shelf -> [Inches]
+positions Shelf{..} = map sum $ (tail . inits) $ concatMap (: [boardThickness]) $ kickerHeight : shelvesAbs
+  where
+    shelvesAbs = map (* availableSpace) shelves'
+    shelves' = map (% (sum shelves)) shelves
+    numHorizontals, numShelves :: Int
+    numShelves = length shelves
+    numHorizontals = numShelves + 1
+    availableSpace = boardLength - kickerHeight - (toRational numHorizontals) * boardThickness
+
+positions' x@Shelf{..} = map (boardLength -) $ positions x
 
-positions' = map (boardLength -) positions
+printPositions :: Shelf -> IO ()
+printPositions x = do
+  mapM_ putStrLn $ formatFeet <$> positions x
+  when (positions x /= reverse (positions' x)) $ do
+    putStrLn "\nReversed:\n"
+    mapM_ putStrLn $ formatFeet <$> positions' x
 
 main :: IO ()
 main = do
-  -- assert $ sum shelves == 1
-  mapM_ putStrLn $ formatFeet <$> positions
-  putStrLn ""
-  mapM_ putStrLn $ formatFeet <$> positions'
-  return ()
+  putStrLn "Piano cubbies:\n"
+  printPositions pianoCubbies
+  putStrLn "\n\nBookshelf:\n"
+  printPositions bookshelf
-- 
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