Re: [PATCH] shr: render table with style

[Lars Magne Ingebrigtsen <larsi@gnus.org>]

Julien Danjou <julien@danjou.info> writes:

> I agree, but I'm just suggesting to optimize things based on real data
> rather than throwing "it will be slower that way".

Real data is great, but it takes a lot of typing to get to it.  Thank
you for doing so.  :-)

> It's obvious that it will be slower if we add more code (thanks). But if
> the table code execution time (you say it's slow) and what I'm proposing
> to add are having a 90/10 execution time ratio, arguing that adding more
> stuff is bloating the execution time is not really helpful. :-D

I find that in Gnus development, you really can't keep carping
"developers, develop...", er, I mean, "speed, speed, speed" enough.  One
adds one more obscure extra functionality because it's nice to have, and
then you find that everything is 50% slower than before.  It's happened
a lot...  and mostly with code I write myself.  :-)

> I've used the following data example to test the rendering:

Nice.

> I've counted 15 color rendering points in it that should be rendered
> correctly. Based on that, I've benchmarked the execution time and the
> number of rendering point correctly done on current master version and
> with my patched version.

I'm not sure I'm seeing all the rendering points, but the obvious ones
were the table/td/td {b,f}gcolor ones, right?

> Benchmark runs with:
> (benchmark-run-compiled 100
>   (shr-insert-document
>     (libxml-parse-html-region
>        (point-min) (point-max))))
>
> With my patch the code is 58 % slower but passes twice more tests (and
> probably more, actually, I did not bother to make the numbers show how
> lame the current code is :-P).

I just did the obvious thing and altered -tag-table and -render-td to do
colourisation like -tag-font, and, tada, with the following and your
test HTML.  Before:

(let ((doc
       (save-excursion
	 (libxml-parse-html-region
	  (goto-char (point-min)) (search-forward "\n\n")))))
  (benchmark-run-compiled 1000 (with-temp-buffer
				 (shr-insert-document doc))))
=> (3.0290269999999997 19 1.0066839999999786)

After adding the -tag-table and -render-td colourisations (that should
be a word):

=> (3.0097929999999997 19 1.0296220000000034)

So that's, er, faster.  Ok, `benchmark-run-compiled' may not be the most
precise benchmarking tool in the world, but...

I didn't try to do TR handling, though, so yours is more ACID-ey.  Or
bordercolor, but I don't really think the latter matters much...

-- 
(domestic pets only, the antidote for overdose, milk.)
  larsi@gnus.org * Lars Magne Ingebrigtsen