Text.PrettyPrint.Final.Extensions.Precedence

A transformer of pretty monads that provides effects for inserting parentheses minimally and correctly.

Precedence information

data PrecEnv ann

A precedence environment contains enough information to determine whether parentheses should be inserted.

Constructors

PrecEnv

Fields

• level :: Int

  The current precedence level of the context

• bumped :: Bool

  A tiebreaker used to distinguish left- and right-associative contexts

• lparen :: (Text, Maybe ann)

  What to show for a left parenthesis. The optional annotation will be applied.

• rparen :: (Text, Maybe ann)

  What to show for a right parenthesis. The optional annotation will be applied.

precEnv0 :: PrecEnv ann

An initial precedence environment that works for languages with parentheses as delimiters.

Precedence effects

askLevel :: (Functor m, MonadReaderPrec ann m) => m Int

What is the current precedence level?

localLevel :: (Functor m, MonadReaderPrec ann m) => (Int -> Int) -> m a -> m a

Run a subcomputation with a modified precedence level.

infl :: MonadPrettyPrec w ann fmt m => Int -> m () -> m () -> m () -> m ()

Display a left-associative infix operator at a precedence level

infr :: MonadPrettyPrec w ann fmt m => Int -> m () -> m () -> m () -> m ()

Display a right-associative infix operator at a precedence level

atLevel :: MonadPrettyPrec w ann fmt m => Int -> m () -> m ()

Run a subcomputation at a particular precedence level

botLevel :: MonadPrettyPrec w ann fmt m => m () -> m ()

Put a subdocument in the lowest precedence context

app :: MonadPrettyPrec w ann fmt m => m () -> [m ()] -> m ()

Perform function application with precedence level <100

askBumped :: (Functor m, MonadReaderPrec ann m) => m Bool

Is the current precedence bumped? See PrecEnv.

The transformer

class MonadReaderPrec ann m | m -> ann where

Precedence follows the structure of a document, so a Reader provides the appropriate dynamic extent of precedence information.

Minimal complete definition

askPrecEnv, localPrecEnv

Methods

askPrecEnv :: m (PrecEnv ann)

What is the current precedence environment? (see ask)

localPrecEnv :: (PrecEnv ann -> PrecEnv ann) -> m a -> m a

Override the precedence environment in a subcomputation. (see local)

Instances

Monad m => MonadReaderPrec ann (PrecT ann m)

Methods

askPrecEnv :: PrecT ann m (PrecEnv ann)

localPrecEnv :: (PrecEnv ann -> PrecEnv ann) -> PrecT ann m a -> PrecT ann m a

(Monad m, MonadReaderPrec ann m) => MonadReaderPrec ann (EnvT env m)

Methods

askPrecEnv :: EnvT env m (PrecEnv ann)

localPrecEnv :: (PrecEnv ann -> PrecEnv ann) -> EnvT env m a -> EnvT env m a

class (MonadPretty w ann fmt m, MonadReaderPrec ann m) => MonadPrettyPrec w ann fmt m | m -> w, m -> ann, m -> fmt

A pretty monad that can read precedence environments

newtype PrecT ann m a

A monad transformer that adds a precedence effects

Constructors

PrecT

Fields

• unPrecT :: ReaderT (PrecEnv ann) m a

Instances

MonadReader r m => MonadReader r (PrecT ann m)

Methods

ask :: PrecT ann m r

local :: (r -> r) -> PrecT ann m a -> PrecT ann m a

reader :: (r -> a) -> PrecT ann m a

MonadState s m => MonadState s (PrecT ann m)

Methods

get :: PrecT ann m s

put :: s -> PrecT ann m ()

state :: (s -> (a, s)) -> PrecT ann m a

MonadWriter o m => MonadWriter o (PrecT ann m)

Methods

writer :: (a, o) -> PrecT ann m a

tell :: o -> PrecT ann m ()

listen :: PrecT ann m a -> PrecT ann m (a, o)

pass :: PrecT ann m (a, o -> o) -> PrecT ann m a

Monad m => MonadReaderPrec ann (PrecT ann m)

Methods

askPrecEnv :: PrecT ann m (PrecEnv ann)

localPrecEnv :: (PrecEnv ann -> PrecEnv ann) -> PrecT ann m a -> PrecT ann m a

MonadTrans (PrecT ann)

Methods

lift :: Monad m => m a -> PrecT ann m a

Monad m => Monad (PrecT ann m)

Methods

(>>=) :: PrecT ann m a -> (a -> PrecT ann m b) -> PrecT ann m b

(>>) :: PrecT ann m a -> PrecT ann m b -> PrecT ann m b

return :: a -> PrecT ann m a

fail :: String -> PrecT ann m a

Functor m => Functor (PrecT ann m)

Methods

fmap :: (a -> b) -> PrecT ann m a -> PrecT ann m b

(<$) :: a -> PrecT ann m b -> PrecT ann m a

Applicative m => Applicative (PrecT ann m)

Methods

pure :: a -> PrecT ann m a

(<*>) :: PrecT ann m (a -> b) -> PrecT ann m a -> PrecT ann m b

(*>) :: PrecT ann m a -> PrecT ann m b -> PrecT ann m b

(<*) :: PrecT ann m a -> PrecT ann m b -> PrecT ann m a

Alternative m => Alternative (PrecT ann m)

Methods

empty :: PrecT ann m a

(<|>) :: PrecT ann m a -> PrecT ann m a -> PrecT ann m a

some :: PrecT ann m a -> PrecT ann m [a]

many :: PrecT ann m a -> PrecT ann m [a]

runPrecT :: PrecEnv ann -> PrecT ann m a -> m a

Run a precedence transformer with some initial precedence environment

mapPrecT :: (m a -> n b) -> PrecT ann m a -> PrecT ann n b

Transform the value returned by a PrecT