Ormolu.Printer.Internal

In most cases import Ormolu.Printer.Combinators instead, these functions are the low-level building blocks and should not be used on their own. The R monad is re-exported from Ormolu.Printer.Combinators as well.

The R monad

data R a

The R monad hosts combinators that allow us to describe how to render AST.

Instances

Monad R

Defined in Ormolu.Printer.Internal

Methods

(>>=) :: R a -> (a -> R b) -> R b

(>>) :: R a -> R b -> R b

return :: a -> R a

fail :: String -> R a

Functor R

Defined in Ormolu.Printer.Internal

Methods

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

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

Applicative R

Defined in Ormolu.Printer.Internal

Methods

pure :: a -> R a

(<*>) :: R (a -> b) -> R a -> R b

liftA2 :: (a -> b -> c) -> R a -> R b -> R c

(*>) :: R a -> R b -> R b

(<*) :: R a -> R b -> R a

runR

Arguments

:: R ()

Monad to run

-> SpanStream

Span stream

-> CommentStream

Comment stream

-> Anns

Annotations

-> Text

Resulting rendition

Run an R monad.

Internal functions

txt

Arguments

:: Text

Text to output

-> R ()

Output a fixed Text fragment. The argument may not contain any line breaks. txt is used to output all sorts of “fixed” bits of syntax like keywords and pipes | in functional dependencies.

To separate various bits of syntax with white space use space instead of txt " ". To output Outputable Haskell entities like numbers use atom.

atom :: Outputable a => a -> R ()

Output Outputable fragment of AST. This can be used to output numeric literals and similar. Everything that doesn't have inner structure but does have an Outputable instance.

space :: R ()

This primitive does not necessarily output a space. It just ensures that the next thing that will be printed on the same line will be separated by a single space from the previous output. Using this combinator twice results in at most one space.

In practice this design prevents trailing white space and makes it hard to output more than one delimiting space in a row, which is what we usually want.

newline :: R ()

Output a newline. First time newline is used after some non-newline output it gets inserted immediately. Second use of newline does not output anything but makes sure that the next non-white space output will be prefixed by a newline. Using newline more than twice in a row has no effect. Also, using newline at the very beginning has no effect, this is to avoid leading whitespace.

Similarly to space, this design prevents trailing newlines and makes it hard to output more than one blank newline in a row.

isLineDirty :: R Bool

Check if the current line is “dirty”, that is, there is something on it that can have comments attached to it.

inci :: R () -> R ()

Increase indentation level by one indentation step for the inner computation. inci should be used when a part of code must be more indented relative to the parts outside of inci in order for the output to be valid Haskell. When layout is single-line there is no obvious effect, but with multi-line layout correct indentation levels matter.

sitcc :: R () -> R ()

Set indentation level for the inner computation equal to current column. This makes sure that the entire inner block is uniformly "shifted" to the right. Only works (and makes sense) when enclosing layout is multi-line.

data Layout

Layout options.

Constructors

SingleLine

Put everything on single line

MultiLine

Use multiple lines

Instances

Eq Layout

Defined in Ormolu.Printer.Internal

Methods

(==) :: Layout -> Layout -> Bool

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

Show Layout

Defined in Ormolu.Printer.Internal

Methods

showsPrec :: Int -> Layout -> ShowS

show :: Layout -> String

showList :: [Layout] -> ShowS

enterLayout :: Layout -> R () -> R ()

Set Layout for internal computation.

vlayout

Arguments

:: R a

Single line

-> R a

Multi line

-> R a

Do one or another thing depending on current Layout.

getLayout :: R Layout

Get current Layout.

Helpers for braces

useBraces :: R () -> R ()

Make the inner computation use braces around single-line layouts.

dontUseBraces :: R () -> R ()

Make the inner computation omit braces around single-line layouts.

canUseBraces :: R Bool

Return True if we can use braces in this context.

Special helpers for comment placement

data CommentPosition

Modes for rendering of pending comments.

Constructors

OnTheSameLine

Put the comment on the same line

OnNextLine

Put the comment on next line

Instances

Eq CommentPosition

Defined in Ormolu.Printer.Internal

Methods

(==) :: CommentPosition -> CommentPosition -> Bool

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

Show CommentPosition

Defined in Ormolu.Printer.Internal

Methods

showsPrec :: Int -> CommentPosition -> ShowS

show :: CommentPosition -> String

showList :: [CommentPosition] -> ShowS

registerPendingCommentLine

Arguments

:: CommentPosition

Comment position

-> Text

Text to output

-> R ()

Register a comment line for outputting. It will be inserted right before next newline. When the comment goes after something else on the same line, a space will be inserted between preceding text and the comment when necessary.

trimSpanStream

Arguments

:: RealSrcSpan

Reference span

-> R ()

Drop elements that begin before or at the same place as given SrcSpan.

nextEltSpan :: R (Maybe RealSrcSpan)

Get location of next element in AST.

popComment :: (RealLocated Comment -> Bool) -> R (Maybe (RealLocated Comment))

Pop a Comment from the CommentStream if given predicate is satisfied and there are comments in the stream.

getEnclosingSpan

Arguments

:: (RealSrcSpan -> Bool)

Predicate to use

-> R (Maybe RealSrcSpan)

Get the first enclosing RealSrcSpan that satisfies given predicate.

withEnclosingSpan :: RealSrcSpan -> R () -> R ()

Set RealSrcSpan of enclosing span for the given computation.

data HaddockStyle

Haddock string style.

Constructors

Pipe

-- |

Caret

-- ^

Asterisk Int

-- *

Named String

-- $

setLastCommentSpan

Arguments

:: Maybe HaddockStyle

HaddockStyle or Nothing if it's a non-Haddock comment

-> RealSrcSpan

Location of last printed comment

-> R ()

Set span of last output comment.

getLastCommentSpan :: R (Maybe (Maybe HaddockStyle, RealSrcSpan))

Get span of last output comment.

Annotations

getAnns :: SrcSpan -> R [AnnKeywordId]

For a given span return AnnKeywordIds associated with it.