Better support for multiline strings

[chshersh]

First of all, thanks a lot for creating this amazing tool! 🎉
I use it daily and it helps me a lot 🤗

While using the issue, I've noticed one potential improvement. Currently, when I edit a single line in a multiline YAML code block, I see the diff between two YAML values as the fully new string instead of detailed highlights in each string (as shown on the screenshot below)

I would be truly wonderful if difftastic could produce a more granular diff in this case! 🙏🏻

Possibly related:

• Highlight the changed lines in a multiline string more prominently #178

Additional information:

• OS: Ubuntu 22.04
• Difftastic version: 0.35.0

[anka-213]

I wonder if it would be possible for difftastic to detect the nested language in these cases, to get full featured diffs even inside strings? But even a simple linewise diff would be an improvement of the current mode of treating strings as atomic.

[Ramblurr]

With the merging of 9133918 this should be possible now right?

I deal with lots of yaml with long multiline strings, and this feature would be really really helpful:

[karlb]

Multiline yaml diffs in one of the rare cases where a normal diff is more readable than difftastic's output. Here's one example:

I see two problems that might be related:

• The unchanged lines are included in the red/green diff
• The bold part with the actual change goes over two lines, while the semantic change is only a single line

So in this case a line-based diff of the multiline part is preferable.

Tested with

Difftastic 0.65.0
Toolchain: 1.90.0
System:    macos aarch64

Thanks for difftastic, it is an excellent tool!