Clear visual indication which code has been executed

[onyxfish]

Okay, first of all, I flipping love this software. It's made me tremendously more productive. Thank you for creating it.

I'm wondering if it would be possible to add a clear visual indication which lines of code have been executed--either a background highlight or marker in the margin. Ideally this visual indication would disappear when that line of code has subsequently been modified.

When I'm doing analysis I find myself jumping around executing lines of code and it's sometimes difficult to tell for certain if I've run all the code that the current block depends on.

[willwhitney]

Glad you like it!

This sounds like a great feature. I'm super busy right now (applying to PhD programs!) but if you're interested in writing a PR for this that would be awesome.

[onyxfish]

I may do that! I'm not at all familiar with the architecture of Atom, but I'll poke at it and see what I can figure out. Thanks!

[willwhitney]

I was thinking about this again today while writing some Julia in Hydrogen. The highlighting version of this would be awesome.

[onyxfish]

Sat down and took a first whack at this. The good news: it's definitely possible. I've got a proof of concept that adds a class to lines in the "selection" case only. Kudos to you for having readable code. The bad news: I can't get the damn class style to show up, nor is the marker invalidation working in the way the documentation describes. I'm certain both of these things are my error. I'm going to take a break and I might take another crack at it later this weekend.

[onyxfish]

Couldn't let it go. I've got it about 75% working on my master: https://github.com/onyxfish/hydrogen

[willwhitney]

What a boss! This is looking really nice.

A couple of things to think about before shooting me a PR:

• You may have to do some funky conditional Less logic to make it look right on light backgrounds too. That's what contrast is doing here: https://github.com/willwhitney/hydrogen/blob/master/styles/hydrogen.less#L17
• These should get cleared when the kernel is reset, just like the bubbles. This is probably the right place for that: https://github.com/willwhitney/hydrogen/blob/master/lib/main.coffee#L107
• Let's make this opt-in with a settings switch for now. You can add a field to the config object: https://github.com/willwhitney/hydrogen/blob/master/lib/main.coffee#L16, and the docs for that are here: https://atom.io/docs/api/v1.1.0/Config

Great work!

[onyxfish]

Sounds great, thanks for the tips. I'll send you a PR as soon as I can get it finished up. (I also need to re-implement your special casing for Ruby.)

C

[wadethestealth]

@BenRussert was this idea dropped because of unfinished or not fit for hydrogen, because I would like to add this to my to-do