Text.PrettyPrint.Leijen.Extended

This module re-exports some of the interface for Text.PrettyPrint.Annotated.Leijen along with additional definitions useful for stack.

It defines a Monoid instance for Doc.

Pretty-print typeclass

class Display a where

Associated Types

type Ann a

Methods

display :: a -> Doc (Ann a)

display :: Show a => a -> Doc (Ann a)

Instances

Display (Doc a)

Associated Types

type Ann (Doc a) :: *

Methods

display :: Doc a -> Doc (Ann (Doc a))

Ansi terminal Doc

type AnsiDoc = Doc AnsiAnn

newtype AnsiAnn

Constructors

AnsiAnn [SGR]

Instances

Eq AnsiAnn

Methods

(==) :: AnsiAnn -> AnsiAnn -> Bool

(/=) :: AnsiAnn -> AnsiAnn -> Bool

Show AnsiAnn

Methods

showsPrec :: Int -> AnsiAnn -> ShowS

show :: AnsiAnn -> String

showList :: [AnsiAnn] -> ShowS

Monoid AnsiAnn

Methods

mempty :: AnsiAnn

mappend :: AnsiAnn -> AnsiAnn -> AnsiAnn

mconcat :: [AnsiAnn] -> AnsiAnn

HasAnsiAnn AnsiAnn

Methods

getAnsiAnn :: AnsiAnn -> AnsiAnn

toAnsiDoc :: Doc AnsiAnn -> AnsiDoc

class HasAnsiAnn a where

Minimal complete definition

getAnsiAnn

Methods

getAnsiAnn :: a -> AnsiAnn

toAnsiDoc :: Doc a -> AnsiDoc

Instances

HasAnsiAnn ()

Methods

getAnsiAnn :: () -> AnsiAnn

toAnsiDoc :: Doc () -> AnsiDoc

HasAnsiAnn AnsiAnn

Methods

getAnsiAnn :: AnsiAnn -> AnsiAnn

toAnsiDoc :: Doc AnsiAnn -> AnsiDoc

hDisplayAnsi :: (Display a, HasAnsiAnn (Ann a), MonadIO m) => Handle -> Int -> a -> m ()

displayAnsi :: (Display a, HasAnsiAnn (Ann a)) => Int -> a -> Text

displayPlain :: Display a => Int -> a -> Text

renderDefault :: Int -> Doc a -> SimpleDoc a

Color combinators

black :: Doc AnsiAnn -> Doc AnsiAnn

red :: Doc AnsiAnn -> Doc AnsiAnn

green :: Doc AnsiAnn -> Doc AnsiAnn

yellow :: Doc AnsiAnn -> Doc AnsiAnn

blue :: Doc AnsiAnn -> Doc AnsiAnn

magenta :: Doc AnsiAnn -> Doc AnsiAnn

cyan :: Doc AnsiAnn -> Doc AnsiAnn

white :: Doc AnsiAnn -> Doc AnsiAnn

dullblack :: Doc AnsiAnn -> Doc AnsiAnn

dullred :: Doc AnsiAnn -> Doc AnsiAnn

dullgreen :: Doc AnsiAnn -> Doc AnsiAnn

dullyellow :: Doc AnsiAnn -> Doc AnsiAnn

dullblue :: Doc AnsiAnn -> Doc AnsiAnn

dullmagenta :: Doc AnsiAnn -> Doc AnsiAnn

dullcyan :: Doc AnsiAnn -> Doc AnsiAnn

dullwhite :: Doc AnsiAnn -> Doc AnsiAnn

onblack :: Doc AnsiAnn -> Doc AnsiAnn

onred :: Doc AnsiAnn -> Doc AnsiAnn

ongreen :: Doc AnsiAnn -> Doc AnsiAnn

onyellow :: Doc AnsiAnn -> Doc AnsiAnn

onblue :: Doc AnsiAnn -> Doc AnsiAnn

onmagenta :: Doc AnsiAnn -> Doc AnsiAnn

oncyan :: Doc AnsiAnn -> Doc AnsiAnn

onwhite :: Doc AnsiAnn -> Doc AnsiAnn

ondullblack :: Doc AnsiAnn -> Doc AnsiAnn

ondullred :: Doc AnsiAnn -> Doc AnsiAnn

ondullgreen :: Doc AnsiAnn -> Doc AnsiAnn

ondullyellow :: Doc AnsiAnn -> Doc AnsiAnn

ondullblue :: Doc AnsiAnn -> Doc AnsiAnn

ondullmagenta :: Doc AnsiAnn -> Doc AnsiAnn

ondullcyan :: Doc AnsiAnn -> Doc AnsiAnn

ondullwhite :: Doc AnsiAnn -> Doc AnsiAnn

Intensity combinators

bold :: Doc AnsiAnn -> Doc AnsiAnn

faint :: Doc AnsiAnn -> Doc AnsiAnn

normal :: Doc AnsiAnn -> Doc AnsiAnn

Selective re-exports from Text.PrettyPrint.Annotated.Leijen

Documents, parametrized by their annotations

data Doc a :: * -> *

The abstract data type Doc a represents pretty documents.

Doc a is an instance of the Show class. (show doc) pretty prints document doc with a page width of 100 characters and a ribbon width of 40 characters.

show (text "hello" <$> text "world")

Which would return the string "hello\nworld", i.e.

hello
world

Instances

Functor Doc

Methods

fmap :: (a -> b) -> Doc a -> Doc b

(<$) :: a -> Doc b -> Doc a

Show (Doc a)

Methods

showsPrec :: Int -> Doc a -> ShowS

show :: Doc a -> String

showList :: [Doc a] -> ShowS

IsString (Doc a)

Methods

fromString :: String -> Doc a

Display (Doc a)

Associated Types

type Ann (Doc a) :: *

Methods

display :: Doc a -> Doc (Ann (Doc a))

type Ann (Doc a)

type Ann (Doc a) = a

Basic combinators

nest :: Int -> Doc a -> Doc a

The document (nest i x) renders document x with the current indentation level increased by i (See also hang, align and indent).

nest 2 (text "hello" <$> text "world") <$> text "!"

outputs as:

hello
  world
!

line :: Doc a

The line document advances to the next line and indents to the current nesting level. Doc aument line behaves like (text " ") if the line break is undone by group.

linebreak :: Doc a

The linebreak document advances to the next line and indents to the current nesting level. Document linebreak behaves like empty if the line break is undone by group.

group :: Doc a -> Doc a

The group combinator is used to specify alternative layouts. The document (group x) undoes all line breaks in document x. The resulting line is added to the current line if that fits the page. Otherwise, the document x is rendered without any changes.

softline :: Doc a

The document softline behaves like space if the resulting output fits the page, otherwise it behaves like line.

softline = group line

softbreak :: Doc a

The document softbreak behaves like empty if the resulting output fits the page, otherwise it behaves like line.

softbreak  = group linebreak

Alignment

align :: Doc a -> Doc a

The document (align x) renders document x with the nesting level set to the current column. It is used for example to implement hang.

As an example, we will put a document right above another one, regardless of the current nesting level:

x $$ y  = align (x <$> y)

test    = text "hi" <+> (text "nice" $$ text "world")

which will be layed out as:

hi nice
   world

hang :: Int -> Doc a -> Doc a

The hang combinator implements hanging indentation. The document (hang i x) renders document x with a nesting level set to the current column plus i. The following example uses hanging indentation for some text:

test  = hang 4 (fillSep (map text
        (words "the hang combinator indents these words !")))

Which lays out on a page with a width of 20 characters as:

the hang combinator
    indents these
    words !

The hang combinator is implemented as:

hang i x  = align (nest i x)

indent :: Int -> Doc a -> Doc a

The document (indent i x) indents document x with i spaces.

test  = indent 4 (fillSep (map text
        (words "the indent combinator indents these words !")))

Which lays out with a page width of 20 as:

    the indent
    combinator
    indents these
    words !

encloseSep :: Doc a -> Doc a -> Doc a -> [Doc a] -> Doc a

The document (encloseSep l r sep xs) concatenates the documents xs separated by sep and encloses the resulting document by l and r. The documents are rendered horizontally if that fits the page. Otherwise they are aligned vertically. All separators are put in front of the elements. For example, the combinator list can be defined with encloseSep:

list xs = encloseSep lbracket rbracket comma xs
test    = text "list" <+> (list (map int [10,200,3000]))

Which is layed out with a page width of 20 as:

list [10,200,3000]

But when the page width is 15, it is layed out as:

list [10
     ,200
     ,3000]

Operators

(<+>) :: Doc a -> Doc a -> Doc a infixr 6

The document (x <+> y) concatenates document x and y with a space in between. (infixr 6)

List combinators

hsep :: [Doc a] -> Doc a

The document (hsep xs) concatenates all documents xs horizontally with (<+>).

vsep :: [Doc a] -> Doc a

The document (vsep xs) concatenates all documents xs vertically with (<$>). If a group undoes the line breaks inserted by vsep, all documents are separated with a space.

someText = map text (words ("text to lay out"))

test     = text "some" <+> vsep someText

This is layed out as:

some text
to
lay
out

The align combinator can be used to align the documents under their first element

test     = text "some" <+> align (vsep someText)

Which is printed as:

some text
     to
     lay
     out

fillSep :: [Doc a] -> Doc a

The document (fillSep xs) concatenates documents xs horizontally with (<+>) as long as its fits the page, than inserts a line and continues doing that for all documents in xs.

fillSep xs  = foldr (</>) empty xs

sep :: [Doc a] -> Doc a

The document (sep xs) concatenates all documents xs either horizontally with (<+>), if it fits the page, or vertically with (<$>).

sep xs  = group (vsep xs)

hcat :: [Doc a] -> Doc a

The document (hcat xs) concatenates all documents xs horizontally with (<>).

vcat :: [Doc a] -> Doc a

The document (vcat xs) concatenates all documents xs vertically with (<$$>). If a group undoes the line breaks inserted by vcat, all documents are directly concatenated.

fillCat :: [Doc a] -> Doc a

The document (fillCat xs) concatenates documents xs horizontally with (<>) as long as its fits the page, than inserts a linebreak and continues doing that for all documents in xs.

fillCat xs  = foldr (\<\/\/\>) empty xs

cat :: [Doc a] -> Doc a

The document (cat xs) concatenates all documents xs either horizontally with (<>), if it fits the page, or vertically with (<$$>).

cat xs  = group (vcat xs)

punctuate :: Doc a -> [Doc a] -> [Doc a]

(punctuate p xs) concatenates all documents in xs with document p except for the last document.

someText = map text ["words","in","a","tuple"]
test     = parens (align (cat (punctuate comma someText)))

This is layed out on a page width of 20 as:

(words,in,a,tuple)

But when the page width is 15, it is layed out as:

(words,
 in,
 a,
 tuple)

(If you want put the commas in front of their elements instead of at the end, you should use tupled or, in general, encloseSep.)

Fillers

fill :: Int -> Doc a -> Doc a

The document (fill i x) renders document x. It than appends spaces until the width is equal to i. If the width of x is already larger, nothing is appended. This combinator is quite useful in practice to output a list of bindings. The following example demonstrates this.

types  = [("empty","Doc a")
         ,("nest","Int -> Doc a -> Doc a")
         ,("linebreak","Doc a")]

ptype (name,tp)
       = fill 6 (text name) <+> text "::" <+> text tp

test   = text "let" <+> align (vcat (map ptype types))

Which is layed out as:

let empty  :: Doc a
    nest   :: Int -> Doc a -> Doc a
    linebreak :: Doc a

fillBreak :: Int -> Doc a -> Doc a

The document (fillBreak i x) first renders document x. It than appends spaces until the width is equal to i. If the width of x is already larger than i, the nesting level is increased by i and a line is appended. When we redefine ptype in the previous example to use fillBreak, we get a useful variation of the previous output:

ptype (name,tp)
       = fillBreak 6 (text name) <+> text "::" <+> text tp

The output will now be:

let empty  :: Doc a
    nest   :: Int -> Doc a -> Doc a
    linebreak
           :: Doc a

Bracketing combinators

enclose :: Doc a -> Doc a -> Doc a -> Doc a

The document (enclose l r x) encloses document x between documents l and r using (<>).

enclose l r x   = l <> x <> r

squotes :: Doc a -> Doc a

Document (squotes x) encloses document x with single quotes "'".

dquotes :: Doc a -> Doc a

Document (dquotes x) encloses document x with double quotes '"'.

parens :: Doc a -> Doc a

Document (parens x) encloses document x in parenthesis, "(" and ")".

angles :: Doc a -> Doc a

Document (angles x) encloses document x in angles, "<" and ">".

braces :: Doc a -> Doc a

Document (braces x) encloses document x in braces, "{" and "}".

brackets :: Doc a -> Doc a

Document (brackets x) encloses document x in square brackets, "[" and "]".

Character documents

Primitive type documents

Semantic annotations

annotate :: a -> Doc a -> Doc a

noAnnotate :: Doc a -> Doc a

Strip annotations from a document. This is useful for re-using the textual formatting of some sub-document, but applying a different high-level annotation.

Rendering

Undocumented

Orphan instances

Monoid (Doc a)

Methods

mempty :: Doc a

mappend :: Doc a -> Doc a -> Doc a

mconcat :: [Doc a] -> Doc a