Re: Header fields in custom footer

[Noeck]

Hi,

I have one more question on this topic:

How can I check whether a header field is present at all?
(Or my main goal: how can I avoid that the code fails?)

This works:
\version "2.19.50"
\header {
  title = "ABC"
}
\paper {
  oddFooterMarkup = #(module-ref $defaultheader 'title)
}
{ a }


This does not for obvious reasons:
oddFooterMarkup = #(module-ref $defaultheader 'maintainer)


Instead of putting all possible headers in a default header like
maintainer = ##f
I would like to check the presence, sth like this pseudocode:

oddFooterMarkup = #(if (in? 'maintainer $defaultheader)
       (module-ref $defaultheader 'maintainer)
       "")

Cheers,
Joram