Skip to content

HORIZON HASKELL Docs lts/ghc-9.14.x7a6c33e2026-10-12Search packagesCtrl K

Theme: |

GHC 9.14.1 · lts/ghc-9.14.x · 7a6c33e · 2026-10-12

Modulebase-4.22.0.0Haskell2010

Text.ParserCombinators.ReadPrec

This module defines parser combinators for precedence parsing.

Contents

Precedences
Precedence operations
Other operations
Converters

Synopsis

newtype ReadPrec
type Prec
value minPrec
value lift
value prec
value step
value reset
value get
value look
value +++
value <++
value pfail
value choice
value readPrec_to_P
value readP_to_Prec
value readPrec_to_S
value readS_to_Prec

Packagebase-4.22.0.0
Exports17
LanguageHaskell2010
LicenceBSD-3-Clause
SourceReadPrec.hs

newtypenewtype ReadPrec a

Instances6Monad, Functor, MonadFail, Applicative, Alternative, MonadPlus

Monad ReadPrecDefined in ghc-internal-9.1401.0 · GHC.Internal.Text.ParserCombinators.ReadPrec
Functor ReadPrecDefined in ghc-internal-9.1401.0 · GHC.Internal.Text.ParserCombinators.ReadPrec
MonadFail ReadPrecDefined in ghc-internal-9.1401.0 · GHC.Internal.Text.ParserCombinators.ReadPrec
Applicative ReadPrecDefined in ghc-internal-9.1401.0 · GHC.Internal.Text.ParserCombinators.ReadPrec
Alternative ReadPrecDefined in ghc-internal-9.1401.0 · GHC.Internal.Text.ParserCombinators.ReadPrec
MonadPlus ReadPrecDefined in ghc-internal-9.1401.0 · GHC.Internal.Text.ParserCombinators.ReadPrec

Precedences

typetype Prec = Int

valueminPrec :: Prec

Precedence operations

valuelift :: ReadP a -> ReadPrec a

Lift a precedence-insensitive ReadP to a ReadPrec.

valueprec :: Prec -> ReadPrec a -> ReadPrec a

(prec n p) checks whether the precedence context is less than or equal to n, and

if not, fails
if so, parses p in context n.

valuestep :: ReadPrec a -> ReadPrec a

Increases the precedence context by one.

valuereset :: ReadPrec a -> ReadPrec a

Resets the precedence context to zero.

Other operations

All are based directly on their similarly-named ReadP counterparts.

valueget :: ReadPrec Char

Consumes and returns the next character. Fails if there is no input left.

valuelook :: ReadPrec String

Look-ahead: returns the part of the input that is left, without consuming it.

value(+++) :: ReadPrec a -> ReadPrec a -> ReadPrec a

Symmetric choice.

value(<++) :: ReadPrec a -> ReadPrec a -> ReadPrec a

Local, exclusive, left-biased choice: If left parser locally produces any result at all, then right parser is not used.

valuepfail :: ReadPrec a

Always fails.

valuechoice :: [ReadPrec a] -> ReadPrec a

Combines all parsers in the specified list.

Converters

valuereadPrec_to_P :: ReadPrec a -> Int -> ReadP a

valuereadP_to_Prec :: (Int -> ReadP a) -> ReadPrec a

valuereadPrec_to_S :: ReadPrec a -> Int -> ReadS a

valuereadS_to_Prec :: (Int -> ReadS a) -> ReadPrec a