Copyright | (c) Francesco Gazzetta 2017 |
---|---|
License | BSD3 (see the file LICENSE) |
Maintainer | francygazz@gmail.org |
Stability | stable |
Portability | portable |
Safe Haskell | Safe |
Language | Haskell2010 |
Accumulators, primarily useful for Polyvariadic
- class Accumulator acc x where
- singleton :: (Accumulator acc x, Monoid acc) => x -> acc
- accumulateMany :: (Foldable f, Accumulator acc x) => f x -> acc -> acc
- newtype AccumulatorSemigroup a = AccumulatorSemigroup {}
Documentation
class Accumulator acc x where Source #
An 'Accumulator c i' supports accumulation of elements of type i in it.
This is different from Semigroup
or Monoid
, where <>
acts between
two values with the same type.
:: x | |
-> acc | |
-> acc | Accumulate a value |
Accumulator [a] a Source # | |
Ord a => Accumulator (Set a) a Source # | |
Semigroup m => Accumulator (AccumulatorSemigroup m) (AccumulatorSemigroup m) Source # | |
singleton :: (Accumulator acc x, Monoid acc) => x -> acc Source #
Accumulate a single value in a Monoid
accumulateMany :: (Foldable f, Accumulator acc x) => f x -> acc -> acc Source #
Strictly accumulate multiple values from a Foldable
, from left to right
newtype AccumulatorSemigroup a Source #
Lift a Semigroup
into an Accumulator. This is a newtype because (<>) isn't always the ideal way of accumulating
Semigroup m => Semigroup (AccumulatorSemigroup m) Source # | |
Semigroup m => Accumulator (AccumulatorSemigroup m) (AccumulatorSemigroup m) Source # | |