On 23 Aug 2014, at 4:49 am, Sean Allred <[log in to unmask]> wrote:



> And I don't mean to advocate that these objects should be able to have

> many (9+) mandatory arguments; I'm far more concerned with the

> homelessness for optional ones.



I think after Frank’s experiments with sectioning, it became apparent that this was a major stumbling block. When a chapter heading can have



1. title

2. toc title

3. header title

4. label

5. unnumbered flag

6. author

7. epigraph

…



it no longer makes sense to require mandatory arguments. On the other hand I do see Joseph’s point that when you have just one or two actually mandatory arguments that writing the following is a bit ugly:



   \UseInstance{crossref}{latex2e}{ label = #1 }% only one mandatory argument



* * *



A model that I think has worked quite well in the LaTeX world is how BibTeX has a notion of “mandatory” and “optional” fields for bibliography references.



Perhaps we could supplement the current xtemplate interface with a keyval-type-argument (one only per interface, of course), in which the optional/mandatory nature of each keyval item within is specified by the document design (and some may well be always mandatory).



So according to the situation you could have either



    \UseInstance{…}{…}{arg one}{arg two}{arg three}



or



    \UseInstance{…}{…}{ arg-one=… , arg-two=…, arg-three=… }



or even a combination of the two:



    \UseInstance{…}{…}{arg one}{ arg-two=…, arg-three=… }



Any thoughts?



Will