Data.Text.Prettyprint.Doc.Render.Util.StackMachine

Definitions to write renderers based on looking at a SimpleDocStream as an instruction tape for a stack machine: text is written, annotations are added (pushed) and later removed (popped).

Simple, pre-defined stack machines

These cover most basic use cases where there is not too much special logic, and all that’s important is how to render text, and how to add/remove an annotation.

renderSimplyDecorated

Arguments

:: Monoid out

=> (Text -> out)

Render plain Text

-> (ann -> out)

How to render an annotation

-> (ann -> out)

How to render the removed annotation

-> SimpleDocStream ann

-> out

Simplest possible stack-based renderer.

For example, here is a document annotated with (), and the behaviour is to write »>>>« at the beginning, and »<<<« at the end of the annotated region:

>>> let doc = "hello" <+> annotate () "world" <> "!"
>>> let sdoc = layoutPretty defaultLayoutOptions doc
>>> T.putStrLn (renderSimplyDecorated id (\() -> ">>>") (\() -> "<<<") sdoc)
hello >>>world<<<!

The monoid will be concatenated in a right associative fashion.

renderSimplyDecoratedA

Arguments

:: (Applicative f, Monoid out)

=> (Text -> f out)

Render plain Text

-> (ann -> f out)

How to render an annotation

-> (ann -> f out)

How to render the removed annotation

-> SimpleDocStream ann

-> f out

Version of renderSimplyDecoratedA that allows for Applicative effects.

General stack machine

These definitions allow defining a full-blown stack machine renderer, allowing for arbitrary peeking, popping and what not.

data StackMachine output style a

Deprecated: Writing your own stack machine is probably more efficient and customizable; also consider using »renderSimplyDecorated(A)« instead

WriterT output StateT [style] a, but with a strict Writer value.

The output type is used to append data chunks to, the style is the member of a stack of styles to model nested styles with.

Instances

Monoid output => Monad (StackMachine output style)

Methods

(>>=) :: StackMachine output style a -> (a -> StackMachine output style b) -> StackMachine output style b

(>>) :: StackMachine output style a -> StackMachine output style b -> StackMachine output style b

return :: a -> StackMachine output style a

fail :: String -> StackMachine output style a

Functor (StackMachine output style)

Methods

fmap :: (a -> b) -> StackMachine output style a -> StackMachine output style b

(<$) :: a -> StackMachine output style b -> StackMachine output style a

Monoid output => Applicative (StackMachine output style)

Methods

pure :: a -> StackMachine output style a

(<*>) :: StackMachine output style (a -> b) -> StackMachine output style a -> StackMachine output style b

liftA2 :: (a -> b -> c) -> StackMachine output style a -> StackMachine output style b -> StackMachine output style c

(*>) :: StackMachine output style a -> StackMachine output style b -> StackMachine output style b

(<*) :: StackMachine output style a -> StackMachine output style b -> StackMachine output style a

execStackMachine :: [styles] -> StackMachine output styles a -> (output, [styles])

Run the renderer and retrive the writing end

pushStyle :: Monoid output => style -> StackMachine output style ()

Add a new style to the style stack.

unsafePopStyle :: Monoid output => StackMachine output style style

Get the topmost style.

If the stack is empty, this raises an error.

unsafePeekStyle :: Monoid output => StackMachine output style style

View the topmost style, but do not modify the stack.

If the stack is empty, this raises an error.

writeOutput :: output -> StackMachine output style ()

Append a value to the output end.