Silkscreen.Precedence

Printing with precedence

class Printer p => PrecedencePrinter p where

Pretty-printing with parenthesis insertion resolving precedence.

Given:

data ArithLevel = Bottom | Add | Mult | Exp | Top
  deriving (Eq, Ord)

(+.) :: (PrecedencePrinter p, Level p ~ ArithLevel) => p -> p -> p
(+.) = assoc Add (surround (pretty " + "))
infixl 6 +.

(*.) :: (PrecedencePrinter p, Level p ~ ArithLevel) => p -> p -> p
(*.) = assoc Mult (surround (pretty " * "))
infixl 7 *.

(^.) :: (PrecedencePrinter p, Level p ~ ArithLevel) => p -> p -> p
(^.) = rightAssoc Exp Top (surround (pretty " ^ "))
infixr 8 ^.

>>> putDoc . runPrec Bottom $ ('pretty' "a" +. 'pretty' "b") *. 'pretty' "c" ^. ('pretty' "d" *. 'pretty' "e")
(a + b) * c ^ (d * e)

Associated Types

type Level p

The type used to represent precedence levels. This is defined as an associated type so that consumers can use e.g. symbolic representations of their DSL’s precedence levels instead of e.g. unsemantic Ints.

This type will usually be Ordered, but this isn’t strictly required so that other means of determining precedence can be provided.

Methods

askingPrec :: (Level p -> p) -> p

Print informed by the current Level.

localPrec :: (Level p -> Level p) -> p -> p

Locally change the Level in a printer.

Instances

PrecedencePrinter p => PrecedencePrinter (Rainbow p)

Defined in Silkscreen.Printer.Rainbow

Associated Types

type Level (Rainbow p)

Methods

askingPrec :: (Level (Rainbow p) -> Rainbow p) -> Rainbow p

localPrec :: (Level (Rainbow p) -> Level (Rainbow p)) -> Rainbow p -> Rainbow p

(Bounded level, Printer a) => PrecedencePrinter (Prec level a)

Defined in Silkscreen.Printer.Prec

Associated Types

type Level (Prec level a)

Methods

askingPrec :: (Level (Prec level a) -> Prec level a) -> Prec level a

localPrec :: (Level (Prec level a) -> Level (Prec level a)) -> Prec level a -> Prec level a

PrecedencePrinter b => PrecedencePrinter (a -> b)

Defined in Silkscreen.Precedence

Associated Types

type Level (a -> b)

Methods

askingPrec :: (Level (a -> b) -> a -> b) -> a -> b

localPrec :: (Level (a -> b) -> Level (a -> b)) -> (a -> b) -> a -> b

setPrec :: PrecedencePrinter p => Level p -> p -> p

Set a constant precedence.

This function does not insert parentheses, and thus should be used when inserting parentheses or otherwise resetting the precedence level.

prec :: (PrecedencePrinter p, Ord (Level p)) => Level p -> p -> p

Set a constant precedence, parenthesizing in higher-precedence contexts.

assoc :: (PrecedencePrinter p, Ord (Level p)) => Level p -> (p -> p -> p) -> p -> p -> p

Make an associative infix combinator at the given level.

nonAssoc :: (PrecedencePrinter p, Ord (Level p)) => Level p -> Level p -> (p -> p -> p) -> p -> p -> p

Make a non-associative infix combinator at the given levels for the operator itself and its operands.

leftAssoc :: (PrecedencePrinter p, Ord (Level p)) => Level p -> Level p -> (p -> p -> p) -> p -> p -> p

Make a left-associative infix combinator at the given levels for the operator itself and its right operand.

rightAssoc :: (PrecedencePrinter p, Ord (Level p)) => Level p -> Level p -> (p -> p -> p) -> p -> p -> p

Make a right-associative infix combinator at the given levels for the operator itself and its left operand.

infix_ :: (PrecedencePrinter p, Ord (Level p)) => Level p -> (p -> p) -> (p -> p) -> (p -> p -> p) -> p -> p -> p

Make an infix combinator at the given level for the operator itself, applying functions to either operand.

Re-exports

module Silkscreen