The \saythanks command chokes when \thanks has been called with a macro that takes (and executes!) another macro as argument:


\newcommand\firstauthorthanks{\thanksdefiner{my thanks}}

\author{First Author \\Institution \thanks{\extractthanks\firstauthorthanks}}

        % need full-width title
            abstract text...

    % works here:

The sequence \extractthanks\firstauthorthanks expands to my thanks, and works when used within the document. Is there any way to call \thanks in this setting with a correct result? The definition of "thanks" for the first author

\newcommand\firstauthorthanks{\thanksdefiner{my thanks}}

is provided externally and should not be changed.

I have tried using \DeclareExpandableDocumentCommand to declare \extractthanks, without success. What kind of treatment would \firstauthorthanks require so that it can be passed safely as argument to \thanks?

  • The argument to \thanks is massaged with \protected@xdef and so the \renewcommand fails miserably. It's quite difficult to understand what you're trying to obtain. – egreg Oct 9 '13 at 20:15
  • @egreg: Right, if I define \thanksdefiner externally and do not change it in \extractthanks, it works. For my application, \thanksdefiner takes 7 arguments, which later have to be extracted from \{first,second,third,...}authorthanks macros. The \newcommand\firstauthorthanks{\thanksdefiner{...}} is a predefined idiom which I don't want to change. – krlmlr Oct 9 '13 at 20:28
  • After the explanation, I'm understanding less. – egreg Oct 9 '13 at 20:31
  • @egreg: \firstauthorthanks is supplied by the user in the \thanksdefiner syntax. Definition of \author is packaged and must read "thanks" information from \firstauthorthanks. That's the situation. I can't answer the "why?" question that I feel coming, because I inherited this setup. Also, I'm willing to keep things that way, because there's a fairly large user base with quite a lot of existing documents that rely on this syntax. – krlmlr Oct 9 '13 at 20:37
  • @egreg: To put it in another way: In the example above, only the line \newcommand\firstauthorthanks{\thanksdefiner{my thanks}} is supplied by the user. Everything else I can change. – krlmlr Oct 9 '13 at 20:39

Avoiding the use of \renewcommand inside \extractthanks solves the issue, at least for me:

\newcommand\firstauthorthanks{\thanksdefiner{my thanks}}

Also, adding the necessary amount of \protection solves the issue, too (don't need to change first part in this case):

\author{First Author \\Institution

I still don't know enough about \protected@xdef to be able to explain any of this. It's just observed behavior...

  • As I said, the argument to \thanks is massaged by \protected@xdef; since \renewcommand makes assignments it fails there, but defining \thanksdefiner essentially as a no-op in advance doesn't suffer from this problem. It remains a mystery why \thanksdefiner should appear in the first place. – egreg Oct 9 '13 at 20:48

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