Copyright	(c) The University of Glasgow 2001
License	BSD-style (see the file LICENSE)
Maintainer	David Terei <code@davidterei.com>
Stability	stable
Portability	portable
Safe Haskell	Safe
Language	Haskell98

Text.PrettyPrint

Contents

The document type
Constructing documents
Predicates on documents
Rendering documents

Description

Provides a collection of pretty printer combinators, a set of API's that provides a way to easily print out text in a consistent format of your choosing.

This module should be used as opposed to the HughesPJ module. Both are equivalent though as this module simply re-exports the other.

Synopsis

data Doc
char :: Char -> Doc
text :: String -> Doc
ptext :: String -> Doc
sizedText :: Int -> String -> Doc
zeroWidthText :: String -> Doc
int :: Int -> Doc
integer :: Integer -> Doc
float :: Float -> Doc
double :: Double -> Doc
rational :: Rational -> Doc
semi :: Doc
comma :: Doc
colon :: Doc
space :: Doc
equals :: Doc
lparen :: Doc
rparen :: Doc
lbrack :: Doc
rbrack :: Doc
lbrace :: Doc
rbrace :: Doc
parens :: Doc -> Doc
brackets :: Doc -> Doc
braces :: Doc -> Doc
quotes :: Doc -> Doc
doubleQuotes :: Doc -> Doc
empty :: Doc
(<>) :: Doc -> Doc -> Doc
(<+>) :: Doc -> Doc -> Doc
hcat :: [Doc] -> Doc
hsep :: [Doc] -> Doc
($$) :: Doc -> Doc -> Doc
($+$) :: Doc -> Doc -> Doc
vcat :: [Doc] -> Doc
sep :: [Doc] -> Doc
cat :: [Doc] -> Doc
fsep :: [Doc] -> Doc
fcat :: [Doc] -> Doc
nest :: Int -> Doc -> Doc
hang :: Doc -> Int -> Doc -> Doc
punctuate :: Doc -> [Doc] -> [Doc]
isEmpty :: Doc -> Bool
render :: Doc -> String
data Style = Style {
- mode :: Mode
- lineLength :: Int
- ribbonsPerLine :: Float
}
style :: Style
renderStyle :: Style -> Doc -> String
fullRender :: Mode -> Int -> Float -> (TextDetails -> a -> a) -> a -> Doc -> a
data Mode
- = PageMode
- | ZigZagMode
- | LeftMode
- | OneLineMode
data TextDetails
- = Chr !Char
- | Str String
- | PStr String

The document type

data Doc Source #

The abstract type of documents. A Doc represents a set of layouts. A Doc with no occurrences of Union or NoDoc represents just one layout.

Instances

Eq Doc Source #

Instance details

Methods

(==) :: Doc -> Doc -> Bool #

(/=) :: Doc -> Doc -> Bool #

Show Doc Source #

Instance details

Methods

showsPrec :: Int -> Doc -> ShowS #

show :: Doc -> String #

showList :: [Doc] -> ShowS #

IsString Doc Source #

Instance details

Methods

fromString :: String -> Doc #

Generic Doc Source #

Instance details

Associated Types

type Rep Doc :: * -> * #

Methods

from :: Doc -> Rep Doc x #

to :: Rep Doc x -> Doc #

Semigroup Doc Source #

Instance details

Methods

(<>) :: Doc -> Doc -> Doc #

sconcat :: NonEmpty Doc -> Doc #

stimes :: Integral b => b -> Doc -> Doc #

Monoid Doc Source #

Instance details

Methods

mempty :: Doc #

mappend :: Doc -> Doc -> Doc #

mconcat :: [Doc] -> Doc #

NFData Doc Source #

Instance details

Methods

rnf :: Doc -> () #

type Rep Doc Source #

Instance details

type Rep Doc = D1 (MetaData "Doc" "Text.PrettyPrint.HughesPJ" "pretty-1.1.3.6-inplace" True) (C1 (MetaCons "Doc" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (Doc ()))))

Constructing documents

Converting values into documents

char :: Char -> Doc Source #

A document of height and width 1, containing a literal character.

text :: String -> Doc Source #

A document of height 1 containing a literal string. text satisfies the following laws:

```
text  s <>  text  t = text  (s++ t)
```
text "" <> x = x, if x non-empty

The side condition on the last law is necessary because text "" has height 1, while empty has no height.

ptext :: String -> Doc Source #

Same as text. Used to be used for Bytestrings.

sizedText :: Int -> String -> Doc Source #

Some text with any width. (text s = sizedText (length s) s)

zeroWidthText :: String -> Doc Source #

Some text, but without any width. Use for non-printing text such as a HTML or Latex tags

int Source #

Arguments

:: Int

-> Doc

int n = text (show n)

integer Source #

Arguments

:: Integer

-> Doc

integer n = text (show n)

float Source #

Arguments

:: Float

-> Doc

float n = text (show n)

double Source #

Arguments

:: Double

-> Doc

double n = text (show n)

rational Source #

Arguments

:: Rational

-> Doc

rational n = text (show n)

Simple derived documents

semi Source #

Arguments

:: Doc

A ';' character

comma Source #

Arguments

:: Doc

A ',' character

colon Source #

Arguments

:: Doc

A : character

space Source #

Arguments

:: Doc

A space character

equals Source #

Arguments

:: Doc

A '=' character

lparen Source #

Arguments

:: Doc

A '(' character

rparen Source #

Arguments

:: Doc

A ')' character

lbrack Source #

Arguments

:: Doc

A '[' character

rbrack Source #

Arguments

:: Doc

A ']' character

lbrace Source #

Arguments

:: Doc

A '{' character

rbrace Source #

Arguments

:: Doc

A '}' character

Wrapping documents in delimiters

parens Source #

Arguments

:: Doc

-> Doc

Wrap document in (...)

brackets Source #

Arguments

:: Doc

-> Doc

Wrap document in [...]

braces Source #

Arguments

:: Doc

-> Doc

Wrap document in {...}

quotes Source #

Arguments

:: Doc

-> Doc

Wrap document in '...'

doubleQuotes Source #

Arguments

:: Doc

-> Doc

Wrap document in "..."

Combining documents

empty :: Doc Source #

The empty document, with no height and no width. empty is the identity for <> , <+> , $$ and $+$ , and anywhere in the argument list for sep , hcat , hsep , vcat , fcat etc.

(<>) :: Doc -> Doc -> Doc infixl 6 Source #

Beside. <> is associative, with identity empty .

(<+>) :: Doc -> Doc -> Doc infixl 6 Source #

Beside, separated by space, unless one of the arguments is empty . <+> is associative, with identity empty .

hcat :: [Doc] -> Doc Source #

List version of <> .

hsep :: [Doc] -> Doc Source #

List version of <+> .

($$) :: Doc -> Doc -> Doc infixl 5 Source #

Above, except that if the last line of the first argument stops at least one position before the first line of the second begins, these two lines are overlapped. For example:

 text "hi" $$ nest 5 (text "there")

lays out as

 hi there

rather than

 hi
 there

$$ is associative, with identity empty , and also satisfies

(x $$ y) <> z = x $$ (y <> z), if y non-empty.

($+$) :: Doc -> Doc -> Doc infixl 5 Source #

Above, with no overlapping. $+$ is associative, with identity empty .

vcat :: [Doc] -> Doc Source #

List version of $$ .

sep :: [Doc] -> Doc Source #

Either hsep or vcat .

cat :: [Doc] -> Doc Source #

Either hcat or vcat .

fsep :: [Doc] -> Doc Source #

"Paragraph fill" version of sep .

fcat :: [Doc] -> Doc Source #

"Paragraph fill" version of cat .

nest :: Int -> Doc -> Doc Source #

Nest (or indent) a document by a given number of positions (which may also be negative). nest satisfies the laws:

```
nest  0 x = x
```
```
nest  k (nest  k' x) = nest  (k+k') x
```

nest  k (x <>  y) = nest  k x <>  nest  k y

nest  k (x $$  y) = nest  k x $$  nest  k y

```
nest  k empty  = empty 
```
x <> nest k y = x <> y, if x non-empty

The side condition on the last law is needed because empty is a left identity for <> .

hang :: Doc -> Int -> Doc -> Doc Source #

hang d1 n d2 = sep [d1, nest n d2]

punctuate :: Doc -> [Doc] -> [Doc] Source #

punctuate p [d1, ... dn] = [d1 <> p, d2 <> p, ... dn-1 <> p, dn]

Predicates on documents

isEmpty :: Doc -> Bool Source #

Returns True if the document is empty

Rendering documents

Default rendering

render :: Doc -> String Source #

Render the Doc to a String using the default Style (see style ).

Rendering with a particular style

data Style Source #

A rendering style. Allows us to specify constraints to choose among the many different rendering options.

Constructors

Style

Fields

mode :: Mode
The rendering mode.
lineLength :: Int
Maximum length of a line, in characters.
ribbonsPerLine :: Float
Ratio of line length to ribbon length. A ribbon refers to the characters on a line excluding indentation. So a lineLength of 100, with a ribbonsPerLine of 2.0 would only allow up to 50 characters of ribbon to be displayed on a line, while allowing it to be indented up to 50 characters.

Instances

Eq Style Source #

Instance details

Methods

(==) :: Style -> Style -> Bool #

(/=) :: Style -> Style -> Bool #

Show Style Source #

Instance details

Methods

showsPrec :: Int -> Style -> ShowS #

show :: Style -> String #

showList :: [Style] -> ShowS #

Generic Style Source #

Instance details

Associated Types

type Rep Style :: * -> * #

Methods

from :: Style -> Rep Style x #

to :: Rep Style x -> Style #

type Rep Style Source #

Instance details

type Rep Style = D1 (MetaData "Style" "Text.PrettyPrint.Annotated.HughesPJ" "pretty-1.1.3.6-inplace" False) (C1 (MetaCons "Style" PrefixI True) (S1 (MetaSel (Just "mode") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 Mode) :*: (S1 (MetaSel (Just "lineLength") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 Int) :*: S1 (MetaSel (Just "ribbonsPerLine") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 Float))))

style :: Style Source #

The default style (mode=PageMode, lineLength=100, ribbonsPerLine=1.5).

renderStyle :: Style -> Doc -> String Source #

Render the Doc to a String using the given Style.

General rendering

fullRender Source #

Arguments

:: Mode

Rendering mode.

-> Int

Line length.

-> Float

Ribbons per line.

-> (TextDetails -> a -> a)

What to do with text.

-> a

What to do at the end.

-> Doc

The document.

-> a

Result.

The general rendering interface. Please refer to the Style and Mode types for a description of rendering mode, line length and ribbons.

data Mode Source #

Rendering mode.

Constructors

PageMode

Normal rendering (lineLength and ribbonsPerLine respected').

ZigZagMode

With zig-zag cuts.

LeftMode

No indentation, infinitely long lines (lineLength ignored), but explicit new lines, i.e., text "one" $$ text "two", are respected.

OneLineMode

All on one line, lineLength ignored and explicit new lines ($$) are turned into spaces.

Instances

Eq Mode Source #

Instance details

Methods

(==) :: Mode -> Mode -> Bool #

(/=) :: Mode -> Mode -> Bool #

Show Mode Source #

Instance details

Methods

showsPrec :: Int -> Mode -> ShowS #

show :: Mode -> String #

showList :: [Mode] -> ShowS #

Generic Mode Source #

Instance details

Associated Types

type Rep Mode :: * -> * #

Methods

from :: Mode -> Rep Mode x #

to :: Rep Mode x -> Mode #

type Rep Mode Source #

Instance details

type Rep Mode = D1 (MetaData "Mode" "Text.PrettyPrint.Annotated.HughesPJ" "pretty-1.1.3.6-inplace" False) ((C1 (MetaCons "PageMode" PrefixI False) (U1 :: * -> *) :+: C1 (MetaCons "ZigZagMode" PrefixI False) (U1 :: * -> *)) :+: (C1 (MetaCons "LeftMode" PrefixI False) (U1 :: * -> *) :+: C1 (MetaCons "OneLineMode" PrefixI False) (U1 :: * -> *)))

data TextDetails Source #

A TextDetails represents a fragment of text that will be output at some point in a Doc.

Constructors

Chr !Char

A single Char fragment

Str String

A whole String fragment

PStr String

Used to represent a Fast String fragment but now deprecated and identical to the Str constructor.

Instances

Eq TextDetails Source #

Instance details