And in pathological cases where even this does not work (as I encountered a few
days ago):
\setbox\scratchbox=\vboxx{content}\ifdim\wd\scratchbox>\zeropoint .. \else ..
\fi
dr. Hans van der Meer
> On 2 Aug 2021, at 17:17, Hans Hagen via ntg-context <ntg-context@ntg.nl>
> wrote:
>
> On 8/2/2021 4:43 PM, Aditya Mahajan via ntg-context wrote:
>> On Mon, 2 Aug 2021, Benjamin Buchmuller via ntg-context wrote:
>>> Hi,
>>>
>>> How can I check if a buffer or block has content (or is empty) before a
>>> \useblocks or \getbuffer statement?
>>>
>>> I would like to typeset a headline only if the buffer/block has been used
>>> in a particular section and want to avoid headlines with empty sections.
>> There may be more efficient ways to do it (since buffers are stored at the
>> lua end), but you can always do \doiftextelse(\getbuffer[...]} to test it
>> buffer creates any output.
> indeed you know there is a way ...
>
> \starttext
>
> \startbuffer[test]
> test
> \stopbuffer
>
> \doifelsebuffer{test} {YES} {NOP}
>
> \permanent\protected\def\doifelsebuffercontent#1%
> {\doifelse{\luaexpr{(string.strip(buffers.getcontent("#1")) ~= "" and
> "yes")}}{yes}}
>
> \startbuffer[test]
> \stopbuffer
>
> \doifelsebuffercontent{test} {YES} {NOP}
>
> \startbuffer[test]
>
> \stopbuffer
>
> \doifelsebuffercontent{test} {YES} {NOP}
>
> \stoptext
>
> if we can agree on a proper name then i can add a (more efficient)
> \doifelse...
>
> Hans
>
>
> -----------------------------------------------------------------
> Hans Hagen | PRAGMA ADE
> Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
> tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
> -----------------------------------------------------------------
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