rc diff: introduce diff-jump, replacing git-diff-goto-source

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.

0 files changed, 0 insertions, 0 deletions