Re: Evaluating a Lua expression at the end

[Kumar Appaiah <kumar@nh4.in>]

On Mon, Apr 13, 2015 at 03:32:04PM +0200, Hans Hagen wrote:
> On 4/13/2015 1:53 PM, Kumar Appaiah wrote:
> >Hi.
> >
> >I am trying to set up a system where I can use Lua to find a total
> >that I can display at the end. For example, if I set a question paper,
> >after each question, I do a \directlua{total = total + 4}, assuming
> >this question has 4 points. At the top of my document, I now want to
> >say "Total points:" and display the value of total.
> >
> >Now, naturally, using \directlua gives me 0, since total is 0 at the
> >beginning. But \latelua didn't seem to be what I am looking for. Could
> >someone please guide me in the right direction?
> 
> forget about latelua ... by the time that kicks in typesetting is done
> already .. you need to go multipass:
> 
> \starttext
> 
> \startluacode
>     local name = nil
>     local temp = 0
> 
>     function document.startwhatever(s)
>         name = s
>         temp = 0
>     end
>     function document.addwhatever(n)
>         temp = temp + n
>         context(n)
>     end
>     function document.stopwhatever()
>         job.variables.save("document:temp:"..name,temp)
>     end
>     function document.getwhatever(s)
>         context(job.variables.collected["document:temp:"..s])
>     end
> \stopluacode
> 
> \def\startwhatever[#1]{\ctxlua{document.startwhatever("#1")}}
> \def\stopwhatever     {\ctxlua{document.stopwhatever()}}
> \def\addwhatever    #1{\ctxlua{document.addwhatever(#1)}}
> \def\getwhatever    #1{\ctxlua{document.getwhatever("#1")}}
> 
> total: \getwhatever{foo}
> 
> \startwhatever[foo]
> 
> test 1: \addwhatever{10}\par
> test 2: \addwhatever{20}\par
> test 3: \addwhatever{30}\par
> 
> \stopwhatever
> 
> \stoptext

Thanks Hans. This is what I needed!

Kumar
-- 
Kumar Appaiah
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