Sstrhsrtj

During my last experiences with cross-referencing on total counts between different files, a problem of counting of chapters and appendices appears.

As a MWE we can use a MWE given here with some modifications.

It happens that a simple command like setcounter{truechapters}{value{totalchapters}-value{chapter}} does not work.

I guess, that the reason is in a wrong using of these values.

The question is how to get three counts (total chapters, appendices and true chapters) in one pdf in a simple and reasonable way?

Note, please, also that I cannot use zlabel like it is described by Heiko here

Here is my MWE:

MyBook.tex:

documentclass{memoir}

usepackage{totcount}

usepackage{assoccnt}



newtotcounter{totalchapters}

DeclareAssociatedCounters{chapter}{totalchapters} % Associate the driven counter `totalchapters` to the master counter `chapter`



AtBeginDocument{

    %% register a counter on the basis of the last chapter in totcounter

    regtotcounter{chapter}

}



newcounter{truechapters}





begin{document}



chapter{A}

chapter{B}

appendix

chapter{C}

chapter{D}

chapter{E}

chapter{F}

chapter{G}

chapter{H}

chapter{I}





There are total{totalchapters} total chapters.





There are total{chapter} appendix chapters.





%here we need to count the difference of two previous counters

%setcounter{truechapters}{value{totalchapters}-value{chapter}} 





There are thetruechapters : true chapters.







end{document}

A screenshot of MyBook.pdf is below:

You can use both the LaTeX2e-kernel-macro addtocounter and the
eTeX-primitive numexpr for calculations.

documentclass{memoir}

usepackage{totcount}

usepackage{assoccnt}



newtotcounter{totalchapters}

DeclareAssociatedCounters{chapter}{totalchapters} % Associate the driven counter `totalchapters` to the master counter `chapter`



AtBeginDocument{

    %% register a counter on the basis of the last chapter in totcounter

    regtotcounter{chapter}

}

newcounter{truechapters}



begin{document}



chapter{A}

chapter{B}

appendix

chapter{C}

chapter{D}

chapter{E}

chapter{F}

chapter{G}

chapter{H}

chapter{I}



There are total{totalchapters} total chapters.



There are total{chapter} appendix chapters.



%here we need to count the difference of two previous counters

setcounter{truechapters}{value{totalchapters}}%

addtocounter{truechapters}{-value{chapter}}%



There are thetruechapters : true chapters.



setcounter{truechapters}{numexprvalue{totalchapters}-value{chapter}relax}%



There are thetruechapters : true chapters.



end{document}

Define three new counters, for the main chapters, for the appendix and for the total.

The trick here is to add code to appendix for saving the number of chapters so far in truechapters and resetting the counter for the number of appendices.

documentclass{memoir}

usepackage{etoolbox}

usepackage{totcount,assoccnt}



newcounter{truechapters}

regtotcounter{truechapters}



newcounter{totalchapters}

newcounter{appendixchapters}

DeclareAssociatedCounters{chapter}{totalchapters,appendixchapters}

regtotcounter{totalchapters}

regtotcounter{appendixchapters}



pretoappendix{%

  % save the number of true chapters

  setcounter{truechapters}{value{chapter}}%

  % reset the number of chapters

  setcounter{appendixchapters}{0}%

}





begin{document}



frontmatter



There are total{totalchapters} total chapters.



There are total{appendixchapters} appendix chapters.



There are total{truechapters} true chapters.



mainmatter



chapter{A}

chapter{B}

appendix

chapter{C}

chapter{D}

chapter{E}

chapter{F}

chapter{G}

chapter{H}

chapter{I}



end{document}

A variant of egreg's solution, this time using the up-to-date xassoccnt package (being the successor of assoccnt), which has a partial support for total counters.

documentclass{memoir}

usepackage{xassoccnt}% Version 1.2 or higher, current version is 1.7



NewTotalDocumentCounter{appendixchapters}

DeclareTotalAssociatedCounters{chapter}{truechapters,totalchapters}



makeatletter

g@addto@macroappendix{%

  SuspendCounters{truechapters}

  AddAssociatedCounters{chapter}{appendixchapters}

}

makeatother



begin{document}



frontmatter



There are TotalValue{totalchapters} total chapters.



There are TotalValue{appendixchapters} appendix chapters.



There are TotalValue{truechapters} true chapters.



mainmatter



chapter{A}

chapter{B}

appendix

chapter{C}

chapter{D}

chapter{E}

chapter{F}

chapter{G}

chapter{H}

chapter{I}



end{document}