License	BSD-3-Clause
Maintainer	Jamie Willis
Stability	unstable
Safe Haskell	Safe-Inferred
Language	Haskell2010

Parsley.Internal.Backend.Machine.Types.Coins

Description

This module exposes Coins and the relevant operations. These are used by constant input analysis to side-step unnecessary length checks and character reads (in the case of lookahead).

Since: 1.5.0.0

Synopsis

data Coins = Coins {
- willConsume :: !Int
- willCache :: !Int
- knownPreds :: !(Maybe CharPred)
}
minCoins :: Coins -> Coins -> Coins
plus1 :: CharPred -> Coins -> Coins
minus :: Coins -> Int -> Coins
canReclaim :: Coins -> Int
pattern Zero :: Coins
one :: CharPred -> Coins
items :: Int -> Coins

Documentation

data Coins Source #

Packages together the known input that can be consumed after a length-check with the number of characters that can be rewound on a lookahead backtrack.

Since: 1.5.0.0

Constructors

Coins
Fields willConsume :: !Int The number of tokens we know must be consumed along the path to succeed. willCache :: !Int knownPreds :: !(Maybe CharPred)

Instances

Instances details

Show Coins Source #
Instance details Defined in Parsley.Internal.Backend.Machine.Types.Coins Methods showsPrec :: Int -> Coins -> ShowS # show :: Coins -> String # showList :: [Coins] -> ShowS #

minCoins :: Coins -> Coins -> Coins Source #

Takes the pairwise min of two Coins values.

Since: 1.5.0.0

plus1 :: CharPred -> Coins -> Coins Source #

Adds 1 to all the Coins values.

Since: 1.5.0.0

minus :: Coins -> Int -> Coins Source #

Since: 1.5.0.0

canReclaim :: Coins -> Int Source #

pattern Zero :: Coins Source #

Makes a Coins value of 0.

Since: 1.5.0.0

one :: CharPred -> Coins Source #

items :: Int -> Coins Source #