prettyprinter-1.7.1: A modern, easy to use, well-documented, extensible pretty-printer.

Safe Haskell | Safe-Inferred
Language | Haskell2010

Prettyprinter.Render.Util.StackMachine

Contents

- Simple, pre-defined stack machines
- General stack machine

Description

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).

Synopsis

- renderSimplyDecorated :: Monoid out => (Text -> out) -> (ann -> out) -> (ann -> out) -> SimpleDocStream ann -> out
- renderSimplyDecoratedA :: (Applicative f, Monoid out) => (Text -> f out) -> (ann -> f out) -> (ann -> f out) -> SimpleDocStream ann -> f out
- data StackMachine output style a
- execStackMachine :: [styles] -> StackMachine output styles a -> (output, [styles])
- pushStyle :: Monoid output => style -> StackMachine output style ()
- unsafePopStyle :: Monoid output => StackMachine output style style
- unsafePeekStyle :: Monoid output => StackMachine output style style
- writeOutput :: output -> StackMachine output style ()

# 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

Instances details

Monoid output => Applicative (StackMachine output style) # |
Instance details Defined in Prettyprinter.Render.Util.StackMachine 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 #
Functor (StackMachine output style) # |
Instance details Defined in Prettyprinter.Render.Util.StackMachine Methods fmap :: (a -> b) -> StackMachine output style a -> StackMachine output style b # (<$) :: a -> StackMachine output style b -> StackMachine output style a #
Monoid output => Monad (StackMachine output style) # |
Instance details Defined in Prettyprinter.Render.Util.StackMachine 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 #

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.