···<date: 2013-01-16, Wednesday>···<from: Procházka Lukáš Ing. - Pontex s. r. o.>···

> Hello,
> 
> On Wed, 16 Jan 2013 12:47:21 +0100, Philipp Gesang <philipp.gesang@alumni.uni-heidelberg.de> wrote:
> 
> >Lookup the correct string from a table?
> 
> thanks for the idea -
> 
> - in other words, we have to keep running results somewhere;

Yes, this is simple because the order of processing doesn’t
change -- as long as the data you aggregate fits into your
memory, of course!

> the algorithm fills a table with texts for each page, and each
> \setlayer takes one value back, so we can simplify to:
> 
</snip>
>     \setlayer[beforetext][preset=righttop]
>       {\framed[width=2in]{\directlua{context(table.remove(userdata.LPr.texts, 1))}}}
</snip>

>       context.startTEXpage { background = "foreground,beforetext" }
>         table.insert(userdata.LPr.texts, "BEF" .. i)
> 
>         context.externalfigure({"cow"},{width="30cm"})
>       context.stopTEXpage()

From my tests calling table.remove() to remove the first element
in a list is extremely inefficient compared to accessing an
array. (For 10^5 elements it’s 1m41.644s vs. 0m0.030s on my
machine.) While we’re at it, table.insert() involves an extra
function call that carries another perfomance penalty, albeit a
much smaller one. Your code should do the same, though.

Regards
Philipp