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.

data TextDetails Source

The TextDetails data type

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

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

int n = text (show n)

integer Source

integer n = text (show n)

float Source

float n = text (show n)

double Source

double n = text (show n)

rational Source

rational n = text (show n)

Simple derived documents

semi Source

comma Source

colon Source

space Source

equals Source

lparen Source

rparen Source

lbrack Source

rbrack Source

lbrace Source

rbrace Source

Wrapping documents in delimiters

parens Source

brackets Source

braces Source

quotes Source

doubleQuotes Source

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 z <> 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.

Rendering with a particular style

data Style Source

A rendering style.

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.

General rendering

fullRender Source

The general rendering interface.