| Copyright | (c) 2006-2011 Harvard University (c) 2011-2012 Geoffrey Mainland (c) 2015-2017 Drexel University |
|---|---|
| License | BSD-style |
| Maintainer | mainland@drexel.edu |
| Stability | provisional |
| Portability | portable |
| Safe Haskell | None |
| Language | Haskell98 |
Text.PrettyPrint.Mainland
Contents
Description
This module is based on A Prettier Printer by Phil Wadler in The Fun of Programming, Jeremy Gibbons and Oege de Moor (eds) http://homepages.inf.ed.ac.uk/wadler/papers/prettier/prettier.pdf
At the time it was originally written I didn't know about Daan Leijen's
pretty printing module based on the same paper. I have since incorporated
many of his improvements. This module is geared towards pretty printing
source code; its main advantages over other libraries are the ability to
automatically track the source locations associated with pretty printed
values and output appropriate #line pragmas and the use of
Text for output.
Synopsis
- data Doc
- text :: String -> Doc
- bool :: Bool -> Doc
- char :: Char -> Doc
- string :: String -> Doc
- int :: Int -> Doc
- integer :: Integer -> Doc
- float :: Float -> Doc
- double :: Double -> Doc
- rational :: Rational -> Doc
- strictText :: Text -> Doc
- lazyText :: Text -> Doc
- star :: Doc
- colon :: Doc
- comma :: Doc
- dot :: Doc
- equals :: Doc
- semi :: Doc
- space :: Doc
- spaces :: Int -> Doc
- backquote :: Doc
- squote :: Doc
- dquote :: Doc
- langle :: Doc
- rangle :: Doc
- lbrace :: Doc
- rbrace :: Doc
- lbracket :: Doc
- rbracket :: Doc
- lparen :: Doc
- rparen :: Doc
- empty :: Doc
- srcloc :: Located a => a -> Doc
- line :: Doc
- softline :: Doc
- softbreak :: Doc
- (<|>) :: Doc -> Doc -> Doc
- (<+>) :: Doc -> Doc -> Doc
- (</>) :: Doc -> Doc -> Doc
- (<+/>) :: Doc -> Doc -> Doc
- (<//>) :: Doc -> Doc -> Doc
- group :: Doc -> Doc
- flatten :: Doc -> Doc
- enclose :: Doc -> Doc -> Doc -> Doc
- squotes :: Doc -> Doc
- dquotes :: Doc -> Doc
- angles :: Doc -> Doc
- backquotes :: Doc -> Doc
- braces :: Doc -> Doc
- brackets :: Doc -> Doc
- parens :: Doc -> Doc
- parensIf :: Bool -> Doc -> Doc
- folddoc :: (Doc -> Doc -> Doc) -> [Doc] -> Doc
- spread :: [Doc] -> Doc
- stack :: [Doc] -> Doc
- cat :: [Doc] -> Doc
- sep :: [Doc] -> Doc
- punctuate :: Doc -> [Doc] -> [Doc]
- commasep :: [Doc] -> Doc
- semisep :: [Doc] -> Doc
- enclosesep :: Doc -> Doc -> Doc -> [Doc] -> Doc
- tuple :: [Doc] -> Doc
- list :: [Doc] -> Doc
- align :: Doc -> Doc
- hang :: Int -> Doc -> Doc
- indent :: Int -> Doc -> Doc
- nest :: Int -> Doc -> Doc
- column :: (Int -> Doc) -> Doc
- nesting :: (Int -> Doc) -> Doc
- width :: Doc -> (Int -> Doc) -> Doc
- fill :: Int -> Doc -> Doc
- fillbreak :: Int -> Doc -> Doc
- faildoc :: Monad m => Doc -> m a
- errordoc :: Doc -> a
- data RDoc
- render :: Int -> Doc -> RDoc
- renderCompact :: Doc -> RDoc
- displayS :: RDoc -> ShowS
- prettyS :: Int -> Doc -> ShowS
- pretty :: Int -> Doc -> String
- prettyCompactS :: Doc -> ShowS
- prettyCompact :: Doc -> String
- displayPragmaS :: RDoc -> ShowS
- prettyPragmaS :: Int -> Doc -> ShowS
- prettyPragma :: Int -> Doc -> String
- displayLazyText :: RDoc -> Text
- prettyLazyText :: Int -> Doc -> Text
- displayPragmaLazyText :: RDoc -> Text
- prettyPragmaLazyText :: Int -> Doc -> Text
- putDoc :: Doc -> IO ()
- putDocLn :: Doc -> IO ()
- hPutDoc :: Handle -> Doc -> IO ()
- hPutDocLn :: Handle -> Doc -> IO ()
The document type
The abstract type of documents.
Constructing documents
Converting values into documents
strictText :: Text -> Doc #
The document consists of the strictText sText s, which should
not contain any newlines.
Simple documents documents
Basic document combinators
srcloc :: Located a => a -> Doc #
The document tags the current line with srcloc x. Only
shown when running locOf xprettyPragma and friends.
(<|>) :: Doc -> Doc -> Doc infixl 3 #
Provide alternative layouts of the same content. Invariant: both arguments must flatten to the same document.
The document will flatten group dd to one line if there is
room for it, otherwise the original d.
Wrapping documents in delimiters
backquotes :: Doc -> Doc #
The document encloses the aligned document backquotes dd in `...`.
parensIf :: Bool -> Doc -> Doc #
The document encloses the document parensIf p dd in parenthesis if
p is True, and otherwise yields just d.
Combining lists of documents
The document comma-space separates commasep dsds, aligning the
resulting document to the current nesting level.
The document semicolon-space separates semisep dsds, aligning the
resulting document to the current nesting level.
enclosesep :: Doc -> Doc -> Doc -> [Doc] -> Doc #
The document separates enclosesep l r p dsds with the punctuation p
and encloses the result using l and r. When wrapped, punctuation appears
at the end of the line. The enclosed portion of the document is aligned one
column to the right of the opening document.
> ws = map text (words "The quick brown fox jumps over the lazy dog") > test = pretty 15 (enclosesep lparen rparen comma ws)
will be layed out as:
(The, quick, brown, fox, jumps, over, the, lazy, dog)
The document separates tuple dsds with commas and encloses them with
parentheses.
The document separates list dsds with commas and encloses them with
brackets.
Alignment and indentation
The document renders hang i dd with a nesting level set to the
current column plus i, not including the first line.
The document renders indent i dd with a nesting level set to the
current column plus i, including the first line.
The document renders the document nest i dd with the current
indentation level increased by i.
column :: (Int -> Doc) -> Doc #
The document is produced by calling column ff with the current
column.
nesting :: (Int -> Doc) -> Doc #
The document is produced by calling column ff with the
current nesting level.
width :: Doc -> (Int -> Doc) -> Doc #
The document is produced by concatenating width d fd with the result
of calling f with the width of the document d.
The document renders document fill i dx, appending
spaces until the width is equal to i. If the width of d is already
greater than i, nothing is appended.
Utilities
The rendered document type
A rendered document.
Constructors
| REmpty | The empty document |
| RChar !Char RDoc | A single character |
| RString !Int String RDoc |
|
| RText Text RDoc | |
| RLazyText Text RDoc | |
| RPos Pos RDoc | Tag output with source location |
| RLine !Int RDoc | A newline with the indentation of the subsequent line. If this is
followed by a |
Document rendering
renderCompact :: Doc -> RDoc #
Render a document without indentation on infinitely long lines. Since no 'pretty' printing is involved, this renderer is fast. The resulting output contains fewer characters.
prettyCompactS :: Doc -> ShowS #
Render and display a document compactly.
prettyCompact :: Doc -> String #
Render and convert a document to a Doc compactly.
displayPragmaS :: RDoc -> ShowS #
Display a rendered document with #line pragmas.
prettyPragmaS :: Int -> Doc -> ShowS #
Render and display a document with #line pragmas.
prettyPragma :: Int -> Doc -> String #
Render and convert a document to a Doc with #line pragmas.
> let loc = Loc (Pos "filename" 3 5 7) (Pos "filename" 5 7 9) > in putStrLn $ prettyPragma 80 $ srcloc loc <> text "foo" </> text "bar" </> text "baz"
will be printed as
foo #line 3 "filename" bar baz
displayLazyText :: RDoc -> Text #
Display a rendered document as Text. Uses a builder.
displayPragmaLazyText :: RDoc -> Text #
Display a rendered document with #line pragmas as Text. Uses a builder.
prettyPragmaLazyText :: Int -> Doc -> Text #
Render and convert a document to Text with #line pragmas. Uses a builder.
Document output
Render a document with a width of 80 and print it to standard output, followed by a newline.