[NTG-context] conditional for undefined references

[Pablo Rodriguez]

Dear list,

consider the following sample:

    \setuppapersize[A8]
    \starttext
    \ConTeXt:

    \in[seac]

    Is it defined?:
    \doifelse{\in[seac]}{??}{undefined}{defined}

    \Lua:

    \ctxlua{context([[{\in[seac]}]])}

    Is it defined?:
    \startlua
    if [[{\in[seac]}]] == "??" then
        context("undefined")
      else
        context("defined")
    end
    \stoplua
    \stoptext


Is there a way to deal with undefined references?

I mean, I need a conditional to handle undefined references.

Why do I have undefined references in my documents? Well, I have almost
90 (Markdown) documents that I need to compile as single documents and
also as one document. When compiling as single documents, there are a
few references to other documents. This is the reason why they are
undefined.

Any chance to be able to catch a "??" output (or \dummyreference) from
"\in[reference]"?

Many thanks for your help,

Pablo
--
http://www.ousia.tk