Sum -is:module

Lifted sum of functors.

Examples

>>> fmap (+1) (InL (Just 1))  :: Sum Maybe [] Int
InL (Just 2)

>>> fmap (+1) (InR [1, 2, 3]) :: Sum Maybe [] Int
InR [2,3,4]

Monoid under addition.

Sum a <> Sum b = Sum (a + b)

Examples

>>> Sum 1 <> Sum 2 <> mempty
Sum {getSum = 3}

>>> mconcat [ Sum n | n <- [3 .. 9]]
Sum {getSum = 42}

Sum (Left q) = 2*q
Sum (Right q) = 2*q+1

Last two are the locations of the '|' before and after the payload

Monoid under addition.

>>> getSum (Sum 1 <> Sum 2 <> mempty)
3

Monoid under group addition. Alternative to the Sum in Data.Monoid, which uses Num instead of AdditiveGroup.

Lifted sum of functors.

Monoid under addition.

>>> getSum (Sum 1 <> Sum 2 <> mempty)
3

Sum a Nat-list.

Example

>>> :kind! Eval (Sum '[1,2,3])
Eval (Sum '[1,2,3]) :: Natural
= 6

Monoid under addition.

>>> getSum (Sum 1 <> Sum 2 <> mempty)
3

A wrapper for an Additive which distinguishes the additive structure

Last two are the locations of the '|' before and after the payload

Sum of field values to be used in an aggregate operation.

Lifted sum of functors.

SUM Corresponds to the `SUM` function.

Sum of WeightedTerm