Text.Layout.Table

This module provides tools to layout text as grid or table. Besides basic things like specifying column positioning, alignment on the same character and length restriction it also provides advanced features like justifying text and fancy tables with styling support.

Layout combinators

Specify how a column is rendered with the combinators in this section. Sensible default values are provided with def.

module Data.Default.Class

Columns

data ColSpec

Specifies the layout of a column.

Instances

Default ColSpec

Methods

def :: ColSpec

column :: LenSpec -> Position H -> AlignSpec -> CutMark -> ColSpec

Smart constructor to specify a column.

numCol :: ColSpec

Numbers are positioned on the right and aligned on the floating point dot.

fixedCol :: Int -> Position H -> ColSpec

Fixes the column length and positions according to the given Position.

fixedLeftCol :: Int -> ColSpec

Fixes the column length and positions on the left.

Length of columns

data LenSpec

Determines how long a column will be.

Instances

Default LenSpec

Methods

def :: LenSpec

expand :: LenSpec

Allows columns to use as much space as needed.

fixed :: Int -> LenSpec

Fixes column length to a specific width.

expandUntil :: Int -> LenSpec

The column will expand as long as it is smaller as the given width.

fixedUntil :: Int -> LenSpec

The column will be at least as wide as the given width.

Positional alignment

data Position orientation

Specifies a position relative from a beginning.

Instances

Eq (Position orientation)

Methods

(==) :: Position orientation -> Position orientation -> Bool

(/=) :: Position orientation -> Position orientation -> Bool

Show (Position orientation)

Methods

showsPrec :: Int -> Position orientation -> ShowS

show :: Position orientation -> String

showList :: [Position orientation] -> ShowS

Default (Position orientation)

Methods

def :: Position orientation

data H

Horizontal orientation.

left :: Position H

right :: Position H

center :: Position orientation

Alignment of cells at characters

data AlignSpec

Determines whether a column will align at a specific letter.

Instances

Default AlignSpec

No alignment is the default.

Methods

def :: AlignSpec

noAlign :: AlignSpec

Don't align text.

charAlign :: Char -> AlignSpec

Align text at the first occurence of a given Char.

predAlign :: (Char -> Bool) -> AlignSpec

Align at the first match of a predicate.

dotAlign :: AlignSpec

Align all text at the first dot from the left. This is most useful for floating point numbers.

Cut marks

data CutMark

Specifies how the place looks where a String has been cut. Note that the cut mark may be cut itself, to fit into a column.

Instances

Default CutMark

A single ellipsis unicode character is used to show cut marks.

Methods

def :: CutMark

noCutMark :: CutMark

Don't show any cut mark when text is cut.

singleCutMark :: String -> CutMark

Use the cut mark on both sides by reversing it on the other.

doubleCutMark :: String -> String -> CutMark

Specify two different cut marks, one for cuts on the left and one for cuts on the right.

ellipsisCutMark :: CutMark

Deprecated: Use def instead.

Basic grid and table layout

type Row a = [a]

An alias for lists, conceptually for values with a horizontal arrangement.

layoutToCells :: [Row String] -> [ColSpec] -> [Row String]

Modifies cells according to the given ColSpec.

layoutToLines :: [Row String] -> [ColSpec] -> [String]

Behaves like layoutToCells but produces lines by joining with whitespace.

layoutToString :: [Row String] -> [ColSpec] -> String

Behaves like layoutToCells but produces a String by joining with the newline character.

Grid modification functions

altLines :: [a -> b] -> [a] -> [b]

Applies functions to given lines in a alternating fashion. This makes it easy to color lines to improve readability in a row.

checkeredCells :: (a -> b) -> (a -> b) -> [[a]] -> [[b]]

Applies functions to cells in a alternating fashion for every line, every other line gets shifted by one. This is useful for distinguishability of single cells in a grid arrangement.

Advanced table layout

data RowGroup

Groups rows together, which should not be visually seperated from each other.

rowsG :: [Row String] -> RowGroup

Group the given rows together.

rowG :: Row String -> RowGroup

Make a group of a single row.

colsG :: [Position V] -> [Col String] -> RowGroup

Uses the columns to create a row group, using the given vertical positionings.

colsAllG :: Position V -> [Col String] -> RowGroup

Uses the columns to create a row group, using the given vertical positioning.

data HeaderColSpec

Specifies how a header is rendered.

Instances

Default HeaderColSpec

Header columns are usually centered.

Methods

def :: HeaderColSpec

headerColumn :: Position H -> Maybe CutMark -> HeaderColSpec

Smart constructor for HeaderColSpec. By omitting the cut mark it will use the one specified in the ColSpec like the other cells in that column.

layoutTableToLines

Arguments

:: [RowGroup]

Groups

-> Maybe ([String], [HeaderColSpec])

Optional header details

-> [ColSpec]

Layout specification of columns

-> TableStyle

Visual table style

-> [String]

Layouts a good-looking table with a optional header. Note that specifying fewer layout specifications than columns or vice versa will result in not showing them.

layoutTableToString :: [RowGroup] -> Maybe ([String], [HeaderColSpec]) -> [ColSpec] -> TableStyle -> String

Text justification

Text can easily be justified and distributed over multiple lines. Such columns can easily be combined with other columns.

justify :: Int -> [String] -> [String]

Fits as many words on a line, depending on the given width. Every line, but the last one, gets equally filled with spaces between the words, as far as possible.

justifyText :: Int -> String -> [String]

Uses words to split the text into words and justifies it with justify.

>>> justifyText 10 "This text will not fit on one line."
["This  text","will   not","fit on one","line."]

Vertical column positioning

type Col a = [a]

An alias for lists, conceptually for values with a vertical arrangement.

colsAsRowsAll :: Position V -> [Col [a]] -> [Row [a]]

Merges multiple columns together and merges them to a valid grid without holes. The following example clarifies this:

>>> colsAsRowsAll top [justifyText 10 "This text will not fit on one line.", ["42", "23"]]
[["This  text","42"],["will   not","23"],["fit on one",""],["line.",""]]

The result is intended to be used with a grid layout function like layoutToCells.

colsAsRows :: [Position V] -> [Col [a]] -> [Row [a]]

Works like colsAsRowsAll, but every position can be specified on its own:

>>> colsAsRows [top, center, bottom] [["a1"], ["b1", "b2", "b3"], ["c3"]]
[["a1","b1",""],["","b2",""],["","b3","c3"]]

top :: Position V

bottom :: Position V

data V

Vertical orientation

Table styles

module Text.Layout.Table.Style

Column modification functions

pad :: Position o -> Int -> String -> String

Assume the given length is greater or equal than the length of the String passed. Pads the given String accordingly, using the position specification.

>>> pad left 10 "foo"
"foo       "

trimOrPad :: Position o -> CutMark -> Int -> String -> String

If the given text is too long, the String will be shortened according to the position specification, also adds some dots to indicate that the column has been trimmed in length, otherwise behaves like pad.

>>> trimOrPad left (singleCutMark "..") 10 "A longer text."
"A longer.."

align :: OccSpec -> AlignInfo -> String -> String

Align a column by first finding the position to pad with and then padding the missing lengths to the maximum value. If no such position is found, it will align it such that it gets aligned before that position.

This function assumes:

ai <> deriveAlignInfo s = ai

alignFixed :: Position o -> CutMark -> Int -> OccSpec -> AlignInfo -> String -> String

Aligns a column using a fixed width, fitting it to the width by either filling or cutting while respecting the alignment.

Column modifaction primitives

Render your own kind of tables with the following functions.

data ColModInfo

Specifies how a column should be modified.

widthCMI :: ColModInfo -> Int

Get the exact width after the modification.

unalignedCMI :: ColModInfo -> ColModInfo

Remove alignment from a ColModInfo. This is used to change alignment of headers, while using the combined width information.

ensureWidthCMI :: Int -> Position H -> ColModInfo -> ColModInfo

Ensures that the modification provides a minimum width, but only if it is not limited.

ensureWidthOfCMI :: String -> Position H -> ColModInfo -> ColModInfo

Ensures that the given String will fit into the modified columns.

columnModifier :: Position H -> CutMark -> ColModInfo -> String -> String

Generates a function which modifies a given String according to Position, CutMark and ColModInfo.

data AlignInfo

Specifies the length before and after a letter.

Instances

Monoid AlignInfo

Since determining a maximum in two directions is not possible, a Monoid instance is provided.

Methods

mempty :: AlignInfo

mappend :: AlignInfo -> AlignInfo -> AlignInfo

mconcat :: [AlignInfo] -> AlignInfo

widthAI :: AlignInfo -> Int

The column width when using the AlignInfo.

deriveColModInfos :: [(LenSpec, AlignSpec)] -> [Row String] -> [ColModInfo]

Derive the ColModInfo by using layout specifications and looking at the cells.

deriveAlignInfo :: OccSpec -> String -> AlignInfo

Generate the AlignInfo of a cell using the OccSpec.

data OccSpec

Specifies an occurence of a letter.