Re: [NTG-context] Evaluating a Lua expression at the end

13 Apr 2015


      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