Stepping through code in list::maps and more

[sanderjson]

More than once I wish I could inspect the live values in a list::map or list::filter or other.

Using a trivial example like this (code below), we can inspect the val but only for the final value of the list. It would be great for the user to be able to cycle through all the values as desired.

In the screenshot below I show one possible UI/UX solution. In this case the arrows could be used to change the value of val, and the user could then debug their code easier.

sample code

let datalist = [0,1,1,2,3,5,8,13,21]
datalist
|>List::map \val -> val * 2

screenshot 1 (current UI)

screenshot 2 (example solution)