11{-# LANGUAGE ScopedTypeVariables #-}
22
3+ -- | This module provides some utility functions to help with aligning pretty
4+ -- printed values by column.
35module Codec.CBOR.Cuddle.Pretty.Columnar (
46 CellAlign (.. ),
57 Row (.. ),
@@ -27,33 +29,46 @@ data Cell ann = Cell
2729 , cellAlign :: CellAlign
2830 }
2931
32+ -- | Creates a cell by pretty printing the input value and then left-aligning
33+ -- the resulting `Doc` within the table.
3034cellL :: Pretty a => a -> Cell ann
3135cellL = (`Cell ` LeftAlign ) . pretty
3236
37+ -- | Creates a cell by pretty printing the input value and then right-aligning
38+ -- the resulting `Doc` within the table.
3339cellR :: Pretty a => a -> Cell ann
3440cellR = (`Cell ` RightAlign ) . pretty
3541
42+ -- | A cell that takes up a cell but has no content.
3643emptyCell :: Cell ann
3744emptyCell = Cell mempty LeftAlign
3845
46+ -- | Checks whether the cell contains a `Doc` with a rendered width of zero.
3947isEmptyCell :: Cell ann -> Bool
4048isEmptyCell (Cell d _) = renderedLen d == 0
4149
50+ -- | A row within the table.
4251newtype Row ann = Row { rowCells :: [Cell ann ]}
4352
53+ -- | Adds a cell at the beginning of the row.
4454prependCell :: Cell ann -> Row ann -> Row ann
4555prependCell c (Row cs) = Row $ c : cs
4656
57+ -- | A row with a single left-aligned document
4758singletonRow :: Doc ann -> Row ann
4859singletonRow x = Row [Cell x LeftAlign ]
4960
61+ -- | `Columnar` is a two-dimensional table of `Doc`s. When rendered, the cells
62+ -- within each row will be aligned with the cells of every other row in the
63+ -- same column.
5064newtype Columnar ann = Columnar { colRows :: [Row ann ]}
5165
5266prettyRow :: [Int -> [Cell ann ] -> Doc ann
5367prettyRow = prettyRow'
5468 where
5569 prettyRow' [] (Cell c _ : cs) = c <> prettyRow' [] cs
5670 prettyRow' _ [] = mempty
71+ prettyRow' _ [Cell c LeftAlign ] = c -- Do not add white space to the last cell
5772 prettyRow' (0 : ws) (_ : cs) = prettyRow' ws cs -- Skip empty columns
5873 prettyRow' (w : ws) (Cell c alignment : cs) =
5974 let
@@ -63,12 +78,23 @@ prettyRow = prettyRow'
6378 in
6479 align' w c <> prettyRow' ws cs
6580
81+ -- | Pretty print the `Columnar` as a table.
6682prettyColumnar :: forall ann . Columnar ann -> Doc ann
6783prettyColumnar (Columnar rows) = vcat $ prettyRow columnWidths . rowCells <$> rows
6884 where
6985 columnWidths =
7086 foldr (zipWith max . fmap (renderedLen . cellDoc) . rowCells) (repeat 0 ) rows
7187
88+ -- | Pretty prints the `Columnar` so that the rows are separated by by the
89+ -- separator `Doc` provided as the third argument and then everything is
90+ -- enclosed within the left and right brackets provided as the first and second
91+ -- argument accordingly. The brackets will be aligned with the separators in the
92+ -- first column, e.g.
93+ -- ```
94+ -- [ foo
95+ -- , bar
96+ -- ]
97+ -- ```
7298columnarListing :: Doc ann -> Doc ann -> Doc ann -> Columnar ann -> Doc ann
7399columnarListing lEnc rEnc _ (Columnar [] ) = lEnc <> rEnc
74100columnarListing lEnc rEnc s (Columnar (row : rows)) =
@@ -80,10 +106,22 @@ columnarListing lEnc rEnc s (Columnar (row : rows)) =
80106 <> line'
81107 <> rEnc
82108
109+ -- | Pretty prints the `Columnar` so that every line after the first has a
110+ -- separator prepended to it. This can be useful when you want to align the rows,
111+ -- but the separator would cause all the other rows after the first to be shifted
112+ -- right by one. The way you use this is you reduce the indentation on the
113+ -- following lines by the width of the separator.
114+ -- ```
115+ -- foo = x
116+ -- , y
117+ -- , z
118+ -- ```
83119columnarSepBy :: Doc ann -> Columnar ann -> Doc ann
84120columnarSepBy _ (Columnar [] ) = mempty
85- columnarSepBy s (Columnar ( x : xs)) =
86- prettyColumnar ( Columnar [x]) <> line' <> prettyColumnar (Columnar $ prependRow <$> xs)
121+ columnarSepBy s (Columnar rows @ ( Row x : xs)) =
122+ prettyRow columnWidths x <> line' <> prettyColumnar (Columnar $ prependRow <$> xs)
87123 where
88124 prependRow (Row (Cell c al : cs)) = Row $ Cell (s <+> c) al : cs
89125 prependRow (Row [] ) = Row []
126+ columnWidths =
127+ foldr (zipWith max . fmap (renderedLen . cellDoc) . rowCells) (repeat 0 ) rows
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