`Scratch` -- a "scratchpad" for your node- or page-scoped variables. In most cases you can do well without `Scratch`, but there are some use cases that aren't solvable with Go's templates without `Scratch`'s help, due to scoping issues.
`Scratch` is added to both `Node` and `Page` -- with the three methods `Set`, `Get` and `Add`. `Set` and `Add` takes a `key` and the `value` to add. Get returns the `value` for the `key` given.
`Set` can store values of any type. `Add` accepts values that support Go's `+` operator.
The scope of the backing data is global for the given `Node` or `Page`, and spans partial and shortcode includes.
**Note:** The examples above uses the special `$` variable, which refers to the top-level node. This is the behavior you most likely want, and will help remove some confusion when using `Scratch` inside page range loops -- and you start inadvertently calling the wrong `Scratch`. But there may be use cases for `{{ .Scratch.Add "key" "some value" }}`.
