Dynamic Inputs

[coatless]

With dynamic inputs, we aim to simplify how code inside a code cell can be executed and automatically update its result. The result is a series of input fields that sit above the code cell or can be relocated elsewhere (?) on the page.

For instance, let's take the following simulation demo:

x <- rnorm(n, 5, 3)
hist(x)

We would expect to see a normal distribution centered at 5 with an SD of 3.

The variable n is omitted from the code but controls how many observations should be generated.

So, if we wanted a slider on the cell variables, we would use inside the cell:

n <- 50 # @param {type:"slider", min:1, max:100, step:1}

For an example of:

x <- rnorm(n, 5, 3)
hist(x)

This ties the input / result change scope to the single interactive code area.

Alternatively, we could consider a shortcode outside of the cell:

{{< slider variable="n" cell-label="my-cell" min=1 max=100 step=1 value=50 >}}

As a result, we would get a document like so:

This was inspired by some of the fun observable toggles Bob Rudis demoed on mastodon.

Design questions:

1. Does it make sense to include this as a feature within the extension?
   • Is it better served if this is an option in a separate extension?
2. Unlike with Shiny, the toggle control is highly responsive as values are updated. Should there be a delay added to avoid small step-wise changes?
3. What kinds of input should be allowed?
   • String input, Number input, Slider input, Drop down input?
4. Should the scope of variables be considered so that all cells involving a variable (e.g. n) be updated?
   • This would require a deep dive into reactive programming at the benefit of not worrying about outdated results on later portions of the page.