Thoughts about the bubbles for hydrogen

[stevenlis]

I love using hydrogen. If there is one thing that I think could be better, I would say the output bubbles.
Here're my thoughts:

1. clear all bubbles after restarting kernel.
2. display a bubble after each line of code.
   For example, If I select three lines of code and run it with hydrogen, only the last line will display a check mark bubbles. Sometimes I have to test the code back and forth, so it's very easy to lost track in the script, especially when I'm cleaning or exploring some datasets. Sometimes I forgot if I run the block or just the last line of it. I have no such issue with nteract/notebook sicne the code is separately by cells.
3. display the order of input like the nteract/notebook instead of a check mark.
   I think it may be even better to show the order of execution.

[BenRussert]

1. clear all bubbles after restarting kernel.

I think this point would be a nice improvement and looks like a good first issue. Would you be interested in making a PR? I will give you a head start with some links to relevant code and answers to any questions you have

2. display a bubble after each line of code.

This issue comes up every now and then. What you are looking for here is cells.

[stevenlis]

@BenRussert Sorry buddy. I'm not a developer yet and mainly using Python for data analysis only. Thanks for mentioning the cells and I guess I did miss something from the doc. I think what I am looking for would be like displaying a buddle with a number to tell me the order of execution after the line that defines a cell. For example:
# %% [1]
print(cell)

# %% [2]
print(cell)

[nikitakit]

1. clear all bubbles after restarting kernel.

Personally, the fact that bubbles aren't cleared has been a huge improvement for me. About a year ago hydrogen would always delete all bubbles when a kernel was restarted, which caused me to lose important experimental results more times than I can count. This behavior was changed in part to support #861 (the "Restart and Re Evaluate Bubbles" command).

The "Hydrogen: Clear Results" command will clear all results bubbles, which is safer because you have to explicitly run it.

That said, I do think that it may be worth marking or re-styling result bubbles that don't correspond to the current execution.

3. display the order of input like the nteract/notebook instead of a check mark.

For a multi-line result view, hovering over the "X" button that closes it will display the execution order. I had originally wanted to display the number somewhere more visible, but my CSS skills weren't up to the task.

I think this would be a very good idea to have. My current thoughts on how to present this in the UI would be to either:

1. Modify the border frame for multi-line results to display the execution count right below the "X" button (single-line results remain unchanged)
2. Or: Display execution counts in the sidebar, where the line numbers are.

[BenRussert]

About a year ago hydrogen would always delete all bubbles when a kernel was restarted, which caused me to lose important experimental results more times than I can count.

Completely forgot about that. Makes sense.

[stevenlis]

@nikitakit I think you're right. Dendenping on what you do and your workflow, the change indeed may be helpful for some people.
I think I may perfer the second option:

execution counts in the sidebar, where the line numbers are