Data.Monoid.Instances.Measured

This module defines the monoid transformer data type Measured.

Documentation

data Measured a

Measured a is a wrapper around the FactorialMonoid a that memoizes the monoid's length so it becomes a constant-time operation. The parameter is restricted to the StableFactorialMonoid class, which guarantees that length (a <> b) == length a + length b.

Instances

Eq a => Eq (Measured a)

Ord a => Ord (Measured a)

Show a => Show (Measured a)

(FactorialMonoid a, IsString a) => IsString (Measured a)

StableFactorialMonoid a => Monoid (Measured a)

StableFactorialMonoid a => PositiveMonoid (Measured a)

StableFactorialMonoid a => MonoidNull (Measured a)

StableFactorialMonoid a => StableFactorialMonoid (Measured a)

StableFactorialMonoid a => FactorialMonoid (Measured a)

(RightGCDMonoid a, StableFactorialMonoid a) => RightGCDMonoid (Measured a)

(LeftGCDMonoid a, StableFactorialMonoid a) => LeftGCDMonoid (Measured a)

(RightReductiveMonoid a, StableFactorialMonoid a) => RightReductiveMonoid (Measured a)

(LeftReductiveMonoid a, StableFactorialMonoid a) => LeftReductiveMonoid (Measured a)

(Eq a, TextualMonoid a, StableFactorialMonoid a) => TextualMonoid (Measured a)

measure :: FactorialMonoid a => a -> Measured a

Create a new Measured value.

extract :: Measured a -> a