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.HughesPJ

Contents

The document type
Constructing documents
Predicates on documents
Utility functions for 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.

Originally designed by John Hughes's and Simon Peyton Jones's.

For more information you can refer to the original paper that serves as the basis for this libraries design: /The Design of a Pretty-printing Library/ by John Hughes, in Advanced Functional Programming, 1995.

Synopsis

data Doc
data TextDetails
- = Chr !Char
- | Str String
- | PStr String
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
maybeParens :: Bool -> Doc -> Doc
maybeBrackets :: Bool -> Doc -> Doc
maybeBraces :: Bool -> Doc -> Doc
maybeQuotes :: Bool -> Doc -> Doc
maybeDoubleQuotes :: Bool -> 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
first :: Doc -> Doc -> Doc
reduceDoc :: Doc -> RDoc
render :: Doc -> String
data Style = Style {
- mode :: Mode
- lineLength :: Int
- ribbonsPerLine :: Float
}
style :: Style
renderStyle :: Style -> Doc -> String
data Mode
- = PageMode
- | ZigZagMode
- | LeftMode
- | OneLineMode
fullRender :: Mode -> Int -> Float -> (TextDetails -> a -> a) -> a -> Doc -> a

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

Instances details

IsString Doc #
Instance details Defined in Text.PrettyPrint.HughesPJ Methods fromString :: String -> Doc Source #
Monoid Doc #
Instance details Defined in Text.PrettyPrint.HughesPJ Methods mempty :: Doc Source # mappend :: Doc -> Doc -> Doc Source # mconcat :: [Doc] -> Doc Source #
Semigroup Doc #
Instance details Defined in Text.PrettyPrint.HughesPJ Methods (<>) :: Doc -> Doc -> Doc Source # sconcat :: NonEmpty Doc -> Doc Source # stimes :: Integral b => b -> Doc -> Doc Source #
Generic Doc #
Instance details Defined in Text.PrettyPrint.HughesPJ Associated Types type Rep Doc :: Type -> Type Source # Methods from :: Doc -> Rep Doc x Source # to :: Rep Doc x -> Doc Source #
Show Doc #
Instance details Defined in Text.PrettyPrint.HughesPJ Methods showsPrec :: Int -> Doc -> ShowS Source # show :: Doc -> String Source # showList :: [Doc] -> ShowS Source #
NFData Doc #
Instance details Defined in Text.PrettyPrint.HughesPJ Methods rnf :: Doc -> () Source #
Eq Doc #
Instance details Defined in Text.PrettyPrint.HughesPJ Methods (==) :: Doc -> Doc -> Bool Source # (/=) :: Doc -> Doc -> Bool Source #
type Rep Doc #
Instance details Defined in Text.PrettyPrint.HughesPJ type Rep Doc = D1 ('MetaData "Doc" "Text.PrettyPrint.HughesPJ" "pretty-1.1.3.6" 'True) (C1 ('MetaCons "Doc" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Doc ()))))

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

Instances details

Generic TextDetails #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Associated Types type Rep TextDetails :: Type -> Type Source # Methods from :: TextDetails -> Rep TextDetails x Source # to :: Rep TextDetails x -> TextDetails Source #
Show TextDetails #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Methods showsPrec :: Int -> TextDetails -> ShowS Source # show :: TextDetails -> String Source # showList :: [TextDetails] -> ShowS Source #
NFData TextDetails #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Methods rnf :: TextDetails -> () Source #
Eq TextDetails #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Methods (==) :: TextDetails -> TextDetails -> Bool Source # (/=) :: TextDetails -> TextDetails -> Bool Source #
type Rep TextDetails #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ type Rep TextDetails = D1 ('MetaData "TextDetails" "Text.PrettyPrint.Annotated.HughesPJ" "pretty-1.1.3.6" 'False) (C1 ('MetaCons "Chr" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 Char)) :+: (C1 ('MetaCons "Str" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String)) :+: C1 ('MetaCons "PStr" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String))))

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 `"..."`

maybeParens :: Bool -> Doc -> Doc Source #

Apply parens to Doc if boolean is true.

maybeBrackets :: Bool -> Doc -> Doc Source #

Apply brackets to Doc if boolean is true.

maybeBraces :: Bool -> Doc -> Doc Source #

Apply braces to Doc if boolean is true.

maybeQuotes :: Bool -> Doc -> Doc Source #

Apply quotes to Doc if boolean is true.

maybeDoubleQuotes :: Bool -> Doc -> Doc Source #

Apply doubleQuotes to Doc if boolean is true.

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

Utility functions for documents

first :: Doc -> Doc -> Doc Source #

first returns its first argument if it is non-empty, otherwise its second.

reduceDoc :: Doc -> RDoc Source #

Perform some simplification of a built up GDoc.

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

Instances details

Generic Style #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Associated Types type Rep Style :: Type -> Type Source # Methods from :: Style -> Rep Style x Source # to :: Rep Style x -> Style Source #
Show Style #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Methods showsPrec :: Int -> Style -> ShowS Source # show :: Style -> String Source # showList :: [Style] -> ShowS Source #
Eq Style #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Methods (==) :: Style -> Style -> Bool Source # (/=) :: Style -> Style -> Bool Source #
type Rep Style #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ type Rep Style = D1 ('MetaData "Style" "Text.PrettyPrint.Annotated.HughesPJ" "pretty-1.1.3.6" '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.

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

Instances details

Generic Mode #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Associated Types type Rep Mode :: Type -> Type Source # Methods from :: Mode -> Rep Mode x Source # to :: Rep Mode x -> Mode Source #
Show Mode #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Methods showsPrec :: Int -> Mode -> ShowS Source # show :: Mode -> String Source # showList :: [Mode] -> ShowS Source #
Eq Mode #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ Methods (==) :: Mode -> Mode -> Bool Source # (/=) :: Mode -> Mode -> Bool Source #
type Rep Mode #
Instance details Defined in Text.PrettyPrint.Annotated.HughesPJ type Rep Mode = D1 ('MetaData "Mode" "Text.PrettyPrint.Annotated.HughesPJ" "pretty-1.1.3.6" 'False) ((C1 ('MetaCons "PageMode" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "ZigZagMode" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "LeftMode" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "OneLineMode" 'PrefixI 'False) (U1 :: Type -> Type)))

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.