### Quick - `\` - Cumulative Reduce

Characters: `\`

Tags: array

The resulting link is monadic, meaning it takes one argument. Note that the arity refers to that of the resulting link, not the number of links this quick consumes.

##### Functionality

Cumulative reduce or n-wise overlapping (simple) reduce.

##### Details

If a nilad appears right before `\`, this does n-wise overlapping reduce. For positive `n`, split the list into overlapping chunks of length `n` (identical to `ṡ` (Split (Length, Overlapping))) and reduce each sublist. For negative `n`, instead of reducing each sublist, slice and remove chunks of length `-n`. For example, `5R ;-2\` returns `[[3, 4, 5], [1, 4, 5], [1, 2, 5], [1, 2, 3]]` - in the first list, `[1, 2]` is removed, in the second list, `[2, 3]` is removed, etc. Note that it does not cumulatively reduce each slice - if you want to do that, you need to manually slice the list with `ṡ` and cumulatively reduce each sublist.

To a reduce a list, begin with the right argument, and then for each element, apply the link to the current accumulator and the incoming value. `a,b,c,... \` is equivalent to `[a, a × b, a × b × c, ...]`. The link must be a dyad; if you want to apply a monad to the two elements, you can use the idiom `,F¥` for some monad `F`, which first pairs the elements and then calls `F` on the result.

##### Syntax
• `<dyad>\` - cumulative reduce
• `<dyad><nilad>\` - n-wise overlapping reduce