It turns out to be an extremely non-trivial problem.

The hidden benefit of (text-based) code environments is that problem is well understood and well solved for information represented as two strings of lines.

Non-text code paradigms fight an uphill battle for utility because they have to each reinvent that wheel, and many of the solutions are not portable to similar problems. I've used the diffing tools in labview, and they definitely work but I wouldn't want to have to rely on them for a large-scale project.

This exists, at least for Word and likely for Excel as well It is also horrible,hard to understand and not useful for most tasks you will use source control for

But is that inherent in any GUI-driven solution, or is it because Microsoft has never prioritized it as a first-class feature? I'd argue it's the latter.

It's certainly not trivial (as Git wasn't trivial), but conceptually, version control strikes me as one of the easier things to translate to a GUI-driven environment. And it's something that should be translated, because version control is a major problem even in domains which have nothing to do with code, e.g. graphic design.

It is not clear to me at all how to make a good version control at GUI apps.

Let’s start with diff - If this is a text doc, diff seems easy. Show old and new text next to each other, somehow highlight new and old version. Immediate problem: what if you choose to highlight “new” with purple + underline, but user is already using purple + underline as a part of their text. Do you choose a different color? Or just hope it is “clear from context”?

Now for spreadsheets: the formula has changed, how do you show this? You can expand the cell to show formulas, but those can he huge, so your document can become unreadable. Or maybe just highlight the cell and let user click on it to see the formula difference - but then you can no longer see the changes at a glance.

What about things with no text representation, like conditional cell format? Are you going to come up with text representation just for display purposes, or are you going to design special text formatting dialog which shows “new” and “old” values?

There are hundreds of questions about GUI diffs which simply do not exist in texts.

I found your response very interesting. It actually makes me think this is doable because "hundreds of questions" doesn't sound too bad. Many projects answer hundreds of questions.

I think these are design issues that you could solve with a bit of work. As an example:

> Immediate problem: what if you choose to highlight “new” with purple + underline, but user is already using purple + underline as a part of their text. Do you choose a different color? Or just hope it is “clear from context”?

Well, the first option that comes to my mind is dimming the full display, except for those rectangular regions which contain changes. I don't know if that's actually the design which makes the most sense, but a designer could mock it up as one of many ideas to see which one makes sense. (I work at a graphic design studio, so I'm fairly familiar with this process.)