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stop relying on undefined in RenderCell

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queue-miscreant 2025-07-29 00:47:03 -05:00
parent 35d97a8a16
commit 4cfca44e6c
1 changed files with 25 additions and 14 deletions
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37
posts/number-number/2/Diagonal.hs
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@ -14,25 +14,27 @@ instance Show RowNumber where
-- Rendered cell data, along with its row number and an optional value to show instead
data RenderCell a = RC {
cellRow :: Maybe RowNumber,
cellForceShow :: Maybe String,
cellData :: a
cellRow :: Maybe RowNumber, -- Nothing if this is a header; Just . RC otherwise
cellForceShow :: Maybe String, -- TODO: Either String a
cellData :: Maybe a
} deriving Functor
-- If a forced value is availaible, use it; otherwise, show the inside
instance Show a => Show (RenderCell a) where
show (RC _ Nothing x) = show x
show (RC _ Nothing (Just x)) = show x
show (RC _ Nothing Nothing) = ""
show (RC _ (Just s) _) = s
-- Lift a RenderCell over Either to an Either over RenderCells
-- If the force-string is set, then a `Left` version with an undefined value is returned
-- If the force-string is set, then a `Left` version with a Nothing value is returned
liftRC :: RenderCell (Either a b) -> Either (RenderCell a) (RenderCell b)
liftRC (RC rn (Just x) _) = Left $ RC rn (Just x) undefined
liftRC (RC rn Nothing (Left v)) = Left $ RC rn Nothing v
liftRC (RC rn Nothing (Right v)) = Right $ RC rn Nothing v
liftRC (RC rn Nothing Nothing) = Left $ RC rn Nothing Nothing
liftRC (RC rn (Just x) _) = Left $ RC rn (Just x) Nothing
liftRC (RC rn Nothing (Just (Left v))) = Left $ RC rn Nothing $ Just v
liftRC (RC rn Nothing (Just (Right v))) = Right $ RC rn Nothing $ Just v
-- Single column with a fixed header and data coming from a row number
newColumn header f = columns f (\_ -> Headed $ RC Nothing (Just header) undefined) [()]
newColumn header f = columns f (\_ -> Headed $ RC Nothing (Just header) Nothing) [()]
-- Numbered rows of data, as opposed to data for rendering
data DiagRow a = DR {
@ -42,7 +44,7 @@ data DiagRow a = DR {
-- Same as `newColumn`, but reads into a DiagRow's row numberRows
-- The display function `f` is used to convert the value to a String
newColumnR header f = newColumn header (\_ c -> RC (Just $ rowNumber c) (Just $ f $ rowNumber c) undefined)
newColumnR header f = newColumn header (\_ c -> RC (Just $ rowNumber c) (Just $ f $ rowNumber c) Nothing)
-- Number rows with the title "Sequence"
numberColumn = newColumnR "Sequence" show
@ -53,9 +55,9 @@ ellipsisColumn = newColumnR "..." (const "...")
-- The ellipsis row is mapped to a cells which always display as ellipses
-- The remaining rows are `Right` if they lie on the main diagonal, or `Left` otherwise
diagBox' n = columns cell headCell [0..n]
where cell _ (DR Ellipsis _) = RC (Just Ellipsis) (Just "...") undefined
cell i (DR rn rd) = RC (Just rn) Nothing $ (if RN i == rn then Right else Left) (rd !! i)
headCell i = Headed $ RC Nothing (Just $ show i) undefined
where cell _ (DR Ellipsis _) = RC (Just Ellipsis) (Just "...") Nothing
cell i (DR rn rd) = RC (Just rn) Nothing $ Just $ (if RN i == rn then Right else Left) (rd !! i)
headCell i = Headed $ RC Nothing (Just $ show i) Nothing
diagBox n = numberColumn <> diagBox' n <> ellipsisColumn
@ -71,6 +73,15 @@ displayRows f = (displayTable .) . tagRows'
rowsOmega :: [[a]] -> [a] -> [DiagRow a]
rowsOmega xs y = zipWith (\x n -> DR (RN n) x) xs [0..] ++ [DR Ellipsis [], DR Omega y]
diagData = rowsOmega [
[1, 2, 3, 4, 5, 6],
[9, 2, 4, 8, 3, 7],
[2, 2, 8, 2, 2, 2],
[2, 3, 9, 3, 9, 9],
[9, 4, 9, 4, 9, 4],
[8, 1, 2, 5, 7, 9]
]
[2, 3, 9, 4, 0, 0]
displayDiagTable ps = rmap style . diagBox
where style = either show id . displayRows (("Red " ++) . show) (map (, ("Green " ++). show) ps)