feat: documentation and box layout

.gitignore

@@ -1,2 +1,3 @@
 .stack-work/
-*~
+*~
+data/

app/Main.hs

@@ -6,7 +6,7 @@ import qualified Sudoku
 import qualified Sudoku.Solve as Solve
 import qualified Sudoku.Render as Render
 import Sudoku.State (State)
-import Options.Applicative (subparser, command, info, Parser, progDesc, execParser)
+import Options.Applicative (subparser, command, info, Parser, progDesc, execParser, idm, customExecParser, ParserPrefs, showHelpOnEmpty, prefs)
 import System.Exit (exitFailure)
 
 data Mode
@@ -21,7 +21,7 @@ parseMode = subparser
 
 main :: IO ()
 main = do
-  mode <- execParser (info parseMode mempty)
+  mode <- customExecParser optparsePreferences (info parseMode idm)
   input <- Text.getContents
   sudoku <- case runParser Sudoku.parse "<stdin>" input of
     Left errorBundle -> (Text.putStr . Text.pack . errorBundlePretty $ errorBundle) >> exitFailure
@@ -34,3 +34,6 @@ main = do
 
       in Render.hints hints
 
+optparsePreferences :: ParserPrefs
+optparsePreferences = prefs showHelpOnEmpty
+

solvedoku.cabal

@@ -1,4 +1,4 @@
-cabal-version: 2.2
+cabal-version: 1.12
 
 -- This file has been generated from package.yaml by hpack version 0.38.1.
 --
@@ -7,22 +7,15 @@ cabal-version: 2.2
 name:           solvedoku
 version:        0.1.0.0
 description:    Please see the README on GitHub at <https://github.com/githubuser/solvedoku#readme>
-homepage:       https://github.com/githubuser/solvedoku#readme
-bug-reports:    https://github.com/githubuser/solvedoku/issues
-author:         Author name here
-maintainer:     example@example.com
-copyright:      2025 Author name here
-license:        BSD-3-Clause
-license-file:   LICENSE
+author:         VegOwOtenks
+maintainer:     vegowotenks@jossco.de
+copyright:      2025 VegOwOtenks
+license:        AGPL-3.0
 build-type:     Simple
 extra-source-files:
     README.md
     CHANGELOG.md
 
-source-repository head
-  type: git
-  location: https://github.com/githubuser/solvedoku
-
 library
   exposed-modules:
       Data.Enum.Util
@@ -38,8 +31,6 @@ library
       Sudoku.Triple
   other-modules:
       Paths_solvedoku
-  autogen-modules:
-      Paths_solvedoku
   hs-source-dirs:
       src
   ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints
@@ -59,8 +50,6 @@ executable solvedoku-exe
   main-is: Main.hs
   other-modules:
       Paths_solvedoku
-  autogen-modules:
-      Paths_solvedoku
   hs-source-dirs:
       app
   ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N
@@ -82,8 +71,6 @@ test-suite solvedoku-test
   main-is: Spec.hs
   other-modules:
       Paths_solvedoku
-  autogen-modules:
-      Paths_solvedoku
   hs-source-dirs:
       test
   ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N

src/Graphics/Text/Box.hs

@@ -16,6 +16,8 @@ import qualified Data.Foldable as Foldable
 import Control.Arrow (Arrow ((***)))
 import qualified Data.Text as Text
 
+-- | A box of text. Has rectangular size, queried with 'size'.
+
 data Box
   = Raw (Array (Int, Int) Char)
   | Grid (Array (Int, Int) Box) (Maybe Border)
@@ -23,6 +25,16 @@ data Box
 data Border = Border
   { top, right, left, bottom, topRight, bottomRight, bottomLeft, topLeft, crosssection, verticalBetween, horizontalBetween :: Char }
 
+-- | Draw grids like this:
+--
+-- @
+-- \/---\
+-- | | |
+-- |-+-|
+-- | | |
+-- \\---/
+-- @
+
 asciiBorder :: Border
 asciiBorder = Border {top='-', right='|', left='|', bottom='-', topRight='\\', bottomRight='/', bottomLeft='\\', topLeft='/', crosssection='+', verticalBetween='|', horizontalBetween='-'}
 
@@ -32,6 +44,8 @@ type Column = Int
 square :: Int -> ((Row, Column) -> Char) -> Box
 square dim f = Raw $ genArray ((0, 0), (dim - 1, dim - 1)) f
 
+-- | All fields will be laid out like in a static grid. There is no compensation for differently sized Boxes in different rows. 
+
 grid :: Maybe Border -> (Int, Int) -> ((Int, Int) -> Box) -> Box
 grid border (rows, cols) f = let
 
@@ -39,6 +53,8 @@ grid border (rows, cols) f = let
 
   in Grid boxes border
 
+-- | Use the 'asciiBorder'.
+
 asciiGrid :: (Int, Int) -> ((Int, Int) -> Box) -> Box
 asciiGrid = grid $ Just asciiBorder
 
@@ -47,6 +63,8 @@ gridCellSize = let
   updateMaxSize box (height, width) = (max height *** max width) $ size box
   in Foldable.foldr updateMaxSize (0, 0) 
 
+-- | The rectangular size of the box.
+
 size :: Box -> (Int, Int)
 size = \case
   Raw chars -> arraySize chars -- snd takes the higher bound, +1 because the array has inclusive ranges
@@ -66,13 +84,15 @@ arraySize = join bimap (+1) . snd . Array.bounds
 orElse :: Maybe a -> a -> a
 orElse option x = Maybe.fromMaybe x option
 
+-- | Look at a single character in the box.
+
 lookup :: Box -> (Int, Int) -> Maybe Char
 lookup b index@(row, col) = case b of
   Raw chars -> chars Array.!? index
   Grid boxes borderM -> let
 
-     (boxRows, boxColumns) = arraySize boxes
      (boxHeight, boxWidth) = gridCellSize boxes
+     (totalHeight, totalWidth) = size b
 
      in case borderM of
 
@@ -83,33 +103,27 @@ lookup b index@(row, col) = case b of
           innerBox <- boxes Array.!? (boxRow, boxCol)
           lookup innerBox (boxRowIndex, boxColIndex)
 
-      Just border -> if
-        | row == 0 && col == 0 -> Just border.topLeft
-        | row == 0 -> Just border.top
-        | col == 0 -> Just border.left
-        -- ^ outer border cases are easy
-        | otherwise -> let
-          row' = row - 1
-          col' = col - 1
-          (boxRow, boxRowIndex) = row' `divMod` (boxHeight + 1)
-          (boxCol, boxColIndex) = col' `divMod` (boxWidth + 1)
+      Just border -> let
+        (boxRow, boxRowIndex) = pred row `divMod` (boxHeight + 1)
+        (boxCol, boxColIndex) = pred col `divMod` (boxWidth + 1)
 
-          in if
-            | boxRowIndex == boxHeight && boxColIndex == boxWidth -> Just $
-              if boxRow == boxRows - 1 && boxCol == boxColumns - 1 -- is it the last row and col?
-                then border.bottomRight
-                else border.crosssection
-            | boxRowIndex == boxHeight -> Just $
-              if boxRow == boxRows - 1 -- is it the last row?
-                then border.bottom
-                else border.horizontalBetween
-            | boxColIndex == boxWidth  -> Just $
-              if boxCol == boxColumns - 1 -- is it the last column?
-                then border.right
-                else border.verticalBetween
-            | otherwise -> do -- it's not at the border between boxes at all
-              innerBox <- boxes Array.!? (boxRow, boxCol)
-              lookup innerBox (boxRowIndex, boxColIndex)
+        in if
+          | row == 0 && col == 0                                -> Just border.topLeft
+          | col == 0 && row == totalHeight - 1                  -> Just border.bottomLeft
+          | row == 0 && col == totalWidth  - 1                  -> Just border.topRight
+          | row == totalHeight - 1 && col == totalWidth - 1     -> Just border.bottomRight
+          | row == 0                                            -> Just border.top
+          | row == totalHeight - 1                              -> Just border.bottom
+          | col == 0                                            -> Just border.left
+          | col == totalWidth - 1                               -> Just border.right
+          | boxRowIndex == boxHeight && boxColIndex == boxWidth -> Just border.crosssection
+          | boxRowIndex == boxHeight                            -> Just border.horizontalBetween
+          | boxColIndex == boxWidth                             -> Just border.verticalBetween
+          | otherwise -> do
+            innerBox <- boxes Array.!? (boxRow, boxCol)
+            lookup innerBox (boxRowIndex, boxColIndex)
+
+-- | Render everything inside, recursively. Produces a rectangular string with line-breaks.
 
 render :: Box -> Text
 render box = let

src/Sudoku/Area.hs

@@ -3,7 +3,7 @@
 {-# LANGUAGE UndecidableInstances #-}
 {-# LANGUAGE InstanceSigs #-}
 {-# LANGUAGE DeriveTraversable #-}
-module Sudoku.Area (Area(..), indexFromDigit) where
+module Sudoku.Area (Area(..), indexFromDigit, digitFromIndex) where
 
 import Sudoku.Triple (Triple, Index)
 import Data.Functor.Compose (Compose(..))
@@ -20,18 +20,10 @@ instance Distributive Area where
   distribute :: Functor f => f (Area a) -> Area (f a)
   distribute = Area . distribute . fmap get
 
-indexFromDigit :: Int -> (Index, Index)
-indexFromDigit i = join bimap toEnum $ i `divMod` 3
-
-digitFromIndex :: (Index, Index) -> Int
-digitFromIndex (outer, inner) = fromEnum outer * 3 + fromEnum inner
-
+-- | Accepts arguments from `0` to `8`. Everything else fails with 'error'
+--
 -- prop> \ i -> digitFromIndex (indexFromDigit (i `mod` 9)) == i `mod` 9
 -- +++ OK, passed 100 tests.
-
--- >>> import Sudoku.Triple (Index(..))
--- >>> digitFromIndex (First, First)
--- 0
 --
 -- >>> indexFromDigit 9
 -- *** Exception: Enum.toEnum{Index}: tag (3) is outside of enumeration's range (0,2)
@@ -39,3 +31,15 @@ digitFromIndex (outer, inner) = fromEnum outer * 3 + fromEnum inner
 -- >>> indexFromDigit 6
 -- (Third,First)
 
+indexFromDigit :: Int -> (Index, Index)
+indexFromDigit i = join bimap toEnum $ i `divMod` 3
+
+-- | Inverse of 'indexFromDigit'
+-- 
+-- >>> import Sudoku.Triple (Index(..))
+-- >>> digitFromIndex (First, First)
+-- 0
+
+digitFromIndex :: (Index, Index) -> Int
+digitFromIndex (outer, inner) = fromEnum outer * 3 + fromEnum inner
+

test/example.s3

@@ -1,9 +0,0 @@
-003020600
-900305001
-001806400
-008102900
-700000008
-006708200
-002609500
-800203009
-005010300