git-diff-goto-source is specific to diffs produced by Git. This patch
generalizes the logic and moves it to a new diff-jump in diff.kak.
The main differences are:
- diff-jump handles plain file diffs (i.e. without the -r option). These
have no "diff" line. This means that it needs to parse +++/--- instead.
- diff-jump can go to the old file, not just the new one.
- diff-jump allows to override the base directory and the number of
directory components to strip.
git-diff-goto-source was implemented with several nested try/catch
blocks. Implementing the extra features would have added more
nesting, redundancy or hidden options. To avoid that, I ported the
parsing logic to Perl (which git.kak already depends on). Maybe
it's possible to do the same in awk.
Potential concerns:
- We could move diff-jump to a new rc/tools/diff.kak but then it's not
obvious where the "diff" module belongs to.
- Should diff "diff-jump -1" be spelled "diff-jump -p1"?
In future, the diff parser could be reused to implement a vimdiff-style
feature: given a diff and the "old" line number, we can compute the
corresponding "new" line number. Perhaps diff-jump should get a -client
argument.
We want to move git-diff-goto-source from rc/tools/git.kak
to rc/filetype/diff.kak (or should we could create
rc/tools/diff.kak?). Either way, create the diff module so we can
formalize this dependency.
Currently this module only provides highlighters, so require it
wherever we reference them.
Keep the diff-select-{file,hunk} commands outside the module because
people might already use them in git buffers.
