On Wed, 26 Jul 2006 11:16:31 -0400, "Cory Echols" <[EMAIL PROTECTED]>
wrote:
>> >> set foldexpr=GetFoldLevel()
>> >>
>> >> function! GetFoldLevel()
>> >> let line_text = getline(v:lnum)
>> >>
>> >> let left_idx = (stridx(line_text, '{') >= 0)
>> >> let right_idx = (stridx(line_text, '}') >= 0)
>> >>
>> >> if left_idx
>> >> if ! right_idx
>> >> return 'a1'
>> >> endif
>> >> elseif right_idx
>> >> return 's1'
>> >> endif
>> >>
>> >> return '='
>> >> endfunction
>>
>> I spoke too soon. I tested it on another file that is 2500 lines long,
>> and it is still unbearably slow. It gets worse towards the end of the
>> file, where it can still take seconds for characters to show up when I
>> type them. I think I'll have to fire up vim in a profiler to see what
>> is causing this slowness, because if this system can compress dozens
>> of channels of video in realtime without breaking a sweat it seems
>> strange that inserting a character in a smallish text file would be a
>> problem.
>Use of return values like 'a1', 's1' and '=' in a fold expression will
>cause significant slowdown. This is because vim has to recursively
>evaluate the fold expression for many lines every time the folding is
>recalculated. Since your expression returns nothing other than these
>particular values, it probably has to run the expression on *every*
>line in your file.
Yes, I understand that. However, when I'm editing a line I would
expect vim to have cached the fold levels of the surrounding lines,
but it seems to reevaluate all the lines above it for every keypress.
One would think everything should stay the same until something
entered on the current line caused a change in the fold level.
In other words, I would expect vim to continuously evaluate the
foldexpr on the current line for every character I typed, and not do
anything else until the fold level changed.
When I open the file, it opens instantly. I can navigate around the
file just fine, and open/close folds. It seems to me that there is
something strange about the way the foldexpr seems to be constantly
reevaluated when I'm typing.
>I tried experimenting with folding expressions for c# a while back. I
>found that I had to return real number values for as many lines as
>possible. (Even when it wasn't necessary for correctness). This gave
>absolute fold levels for many lines and limited the recursive
>evaluation that vim had to use in situations where I had to return an
>'a1', 's1' or '='. This was the only way I could get acceptable
>performance.
How do you do your folding? I'm not sure how I could do that the way I
like to do my folding. :( Maybe I'll resort to just modifying the vim
source to change the way foldmethod=marker works.
--
Be seeing you.
