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

> Now, I have a code which does much expected, but I'm not able to pass the desired content to setups/layer:
> 
> ----
> \setupbodyfont[30pt]
> 
> \starttext
>   A
> 
>   \definelayer  [beforetext][width=\overlaywidth,height=\overlayheight]
>   \defineoverlay[beforetext][{\setups[beforetext]\tightlayer[beforetext]}]
> 
>   \startsetups[beforetext]
>     \setlayer[beforetext][preset=righttop]{\framed[width=2in]{\directlua{context(userdata.LPr.text)}}}
>   \stopsetups
> 
>   \startluacode
>     userdata = userdata or {}
>     userdata.LPr = userdata.LPr or {}
> 
>     for i = 1, 2 do
>       context.startTEXpage{background="foreground,beforetext"}
>         userdata.LPr.text = "BEF" .. i
> 
>         context.externalfigure({"cow"},{width="30cm"})
>       context.stopTEXpage()
>     end
>   \stopluacode
> 
>   Z
> \stoptext
> ----
> 
> Both images of the cow have "BEF2" in the top right corner, but there should be "BEF1" on the former and "BEF2" on the latter.
> 
> I'm trying to pass the text string ("BEF" .. i) via userdata, but it doesn't work.

Afair entire Lua snippet is evaluated first, so any calls to TEX
are delayed until after the loop is executed. Thus the layer is
drawn only when LPr.text already has the final value. But I’m not
entirely sure that’s the correct explanation.

> So how to do it?

Lookup the correct string from a table?

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\setupbodyfont[30pt]

\starttext
  A

  \definelayer  [beforetext][width=\overlaywidth,height=\overlayheight]
  \defineoverlay[beforetext][{\setups[beforetext]\tightlayer[beforetext]}]

  \startsetups[beforetext]
    \setlayer[beforetext][preset=righttop]
      {\framed[width=2in]{\directlua{userdata.LPr.get_label()}}}
  \stopsetups

  \startluacode
    userdata = userdata or { }
    userdata.LPr = userdata.LPr or { }

    local labels  = { }
    local current = 0

    userdata.LPr.get_label = function ( )
      current = current + 1
      context(labels[current])
    end

    for i = 1, 2 do
      context.startTEXpage { background = "foreground,beforetext" }
        labels[i] = "BEF" .. i
        context.externalfigure({"cow"},{width="30cm"})
      context.stopTEXpage()
    end
  \stopluacode

  Z
\stoptext
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Regards
Philipp