[Vim-latex-devel] New Idea for vim-latex

[Srinath A. <sr...@fa...>]

Hello all,

Its been a long time since the list has seen any emails... I've been
busy and it looks like other than the occassional, "why can I not use my
alt keys" email, there have been no major bugs.

Recently, I was thinking of the next cool thing which could be done in
latex-suite. An idea came up while talking with a friend... I've written
up a description of the idea etc... Please take a look and see if you
think its interesting... I am open to ideas on how to implement this.

Idea follows:

Normally, we view the diff between two text files on a line by line basis.
This works fine for code where most logical structure is demarcated on a
line by line basis. (obfuscators notwithstanding). However, for flowing
text, which latex files resemble more than code, it does not quite make
sense to have differences highlighted on a line by line basis. "Units" of
language can be thought to be sentences. The idea is therefore, a way to
view a diff between two files in a non line by line manner.

Vertically diffsplit windows are also something which work only for line by
line diffs. So for example, suppose one of the files is this:

==================================================
Vertically diffsplit windows are also something
which work only for line by line diffs. For diffs
which do not follow the constraint of end of
lines, the most intuitive way to view diffs seems
to be to have a single window having one version
of the file which the differences basically shown
interpersed in the same view.
==================================================

and another is this

==================================================
Vertically diffsplit windows are also something
which work only for line by line diffs. For diffs
which do not follow the constraint of eol's, the
most intuitive way to view differences between
files seems to be to have a single window having
one version of the file which the differences
basically shown interpersed in the same view.
==================================================

Note how the change from "end of line" to "eol" makes two lines change,
although logically, it was only one change. If we run a simple diff between
the two files using vim's native diffsplit, then apart from the first two
lines which are identical, every other line will show a diff. In actual fact,
there are only a couple of changes:

end of lines -> eol's
diffs -> differences between files

So what is needed is obviously a way to convey to the user the two actual
differences. This is a two part problem:

1. Calculating a difference which is not not line by line but sentence by
     sentence or even word by word. I beleive that this is an easy problem.
     I already have written up a simple python program which prints the word by
     difference. So for example, for the two files above, it would generate the
     following output:

      ==================================================
      Vertically diffsplit windows are also something
      which work only for line by line diffs. For diffs
      which do not follow the constraint of <+end of
      lines+><-eol's->, the most intuitive way to view <+diffs+><-differences 
between
      files-> seems
      to be to have a single window having one version
      of the file which the differences basically shown
      interpersed in the same view.
      ==================================================

2. Find a way to convey this diference to the user in a easily graspable way.
     This in my opinion is the hard part. Ideally, if Vim had in-line folding,
     the "<+original text+>" would be folded away and we would show a little "?"
     in its place. The "<-new text->" would be shown with the "<-" and "->"
     parts folded away and the "new text" colored differently. I tried Vince
     Ngeri's conceal patch and couldn't get it to work quite reliably...
     Whenever I split another window, strange things happen to the
     highlighting... The concealed text reappears etc... If someone can get it
     to work robustly, that will be cool. If someone can think of a completely
     different way to present the diff without the conceal patch, that will be
     even cooler. (I cannot think of a way).

Thanks,
Srinath