How to access reactive dependencies for display and navigation? #25
Description
How can I access the information about dependencies of akernel to use it for JupyterLab extensions?
What would be the right entry point for that?
Lets say I have a JupyterLab extension that is able to access a notebook cell model:
let notebook = __tryToGetNotebook(app);
if(notebook){
let cellModels = notebook.model.cells
for(let cellIndex=0; cellIndex < cellModels.length; cellIndex++){
let cellModel = cellModels.get(cellIndex);
let dependencies = __getDependencies(cellModel, notebook); //<= how to implement this?
}
}
=> Is it possible to ask the cell for its dependencies? Or would I have to somehow directly communicate with akernel or ipyx?
Related:
- Improvement: highlight updating cells in reactive mode #24
- https://stackoverflow.com/questions/69539309/how-to-monitor-state-of-observales-in-reactive-calculations
Some possible use cases:
A. Show neighboring cell dependencies in a dependency view when focusing a distinct cell.
The corresponding terms in obsservablehq are "Visual Dataflow" and "Minimap":
https://observablehq.com/@observablehq/introducing-visual-dataflow
B. Generate a full dependency graph
Could look similar to
https://observablehq.com/@observablehq/notebook-visualizer
https://observablehq.com/@observablehq/notebook-visualizer-elk-edition
C. Generate editable flow chart from akernel notebook cells
Maybe combine akernel with a view of ipyspaghetti or node-red, so that a user gets an alternative GUI to edit the notebook cells in some sort of flow chart.
https://github.com/cphyc/ipyspaghetti
D. Navigate between dependent cells.
Similar to the navigation features in a code IDE, the dependency information could be used to
- Jump to a cell where some input comes from
- Show usages of some output and jump to it
https://www.jetbrains.com/help/pycharm/navigating-through-the-source-code.html#go_to_declaration
Activity
davidbrochart commented on Oct 27, 2021
In akernel, dependencies are not cell based but variable based. When you assign to a variable, it keeps track of the variables that are used on the right hand side.
So indeed I think you would have to communicate with the variable, which is an ipyx.X object. I think some of the use cases you mentioned could become possible by implementing the functionality in ipyx as a widget. In particular, the dependency graph could be interesting.
davidbrochart commented on Oct 29, 2021
#28 adds support for DAG visualization.