[TENTATIVE PATCH] Digraph implementation for Evil

[Vegard Øye]

On 2011-05-19 19:23 +0200, Nikolai Weibull wrote:

> OK, I’ve created a merge request on gitorious:
>
> https://gitorious.org/evil/evil/merge_requests/1
>
> I only wrote one test.  I would appreciate it if you wrote some more
> so that I can learn by example.  Also, please tell me if you want
> something other than merge requests on gitorious.

Wow, it looks like you have done a very throughout job of implementing
digraphs. Do you want digraph.el to be part of Evil, or do you want to
distribute it as a standalone library? If the former, it should be
renamed to evil-digraphs.el and loaded in evil.el, and I may make some
modifications to it. If the latter, I would appreciate a license tag
(for example, GPLv2) to make it clear that the file is freely
distributable.

With regard to testing, most of our tests fall into the "vimgolf"
category: performing a key sequence on a test buffer. The main benefit
of such tests is that they are implementation independent. Of course,
the implementation should be tested too, and a common approach is to
feed values into a function and compare the output with the expected
output. `digraph-find' could be tested in this way, e.g.,

    (ert-deftest test-digraph-find ()
      "Test `digraph-find'"
      (should (eq (digraph-find ?L ?F) ?\n))
      (should (eq (digraph-find ?S ?P) ?\ )))

This is also a good way to check edge cases, such as incomplete or
invalid input. (Should it throw an error? Then verify it with
`should-error'.)

I haven't handled merge requests on Gitorious before; the common
approach has been to commit the changes locally, export the commit
with "git format-patch", and post the patch on the mailing list.
Anyhow, I'll merge once I receive a reply to the questions above.

-- 
Vegard