Count pages & warning

Question

I want to display a warning message if the number of pages is out of some range. In particular I want to count only pages between \mainmatter and \backmatter. But I don't know how. Googling I found this useful answer but it must be adapted. Specifically I want to specify range as [10,40] (number of pages between 10 and 40 inclusive), [10,-1] (at least 10 pages) or [-1,40] (no more than 40 pages). I prefer ranges with inclusive bounds, but it is not important. Moreover I want to exclude blank pages. In the warning would be useful show current number of pages.

score 1 · Accepted Answer · answered Jul 10 '22 at 15:57

You need to redefine \cleardoublepage and \backmatter. I also define a counter that takes care of the skipped pages. If there is no \backmatter, the task is performed “at very end”. In each case, we need to subtract 1 from the page number, because the page counter has been stepped.

\documentclass[a4paper]{book}
\usepackage{atveryend}
\usepackage{lipsum}
\makeatletter
\newcommand{\mainpagerange}[2]{%
  \edef\lorenzo@minpages{#1}%
  \edef\lorenzo@maxpages{#2}%
}
\newif\iflorenzo@backmatter
\renewcommand{\backmatter}{%
  \lorenzo@backmattertrue
  \if@openright
    \cleardoublepage
  \else
    \clearpage
  \fi
  \lorenzo@check
  @mainmatterfalse
}
% in case there is no \backmatter
\AtVeryEndDocument{%
  \iflorenzo@backmatter
  \else
    \lorenzo@check
  \fi
}
\newcounter{lorenzo@skippage}
\renewcommand{\cleardoublepage}{%
  \clearpage
  \if@twoside
    \ifodd\c@page
    \else
      \stepcounter{lorenzo@skippage}%
      \hbox{}\newpage
      \if@twocolumn
        \hbox{}\newpage
      \fi
    \fi
  \fi
}
\newcommand{\lorenzo@check}{%
  \edef\lorenzo@pages{\the\numexpr\value{page}-\value{lorenzo@skippage}-1\relax}%
  \ifnum\lorenzo@pages<\lorenzo@minpages
    \lorenzo@warning{less}{\lorenzo@minpages}%
  \fi
  \ifnum\lorenzo@maxpages<0
  \else
    \ifnum\lorenzo@pages>\lorenzo@maxpages
      \lorenzo@warning{more}{\lorenzo@maxpages}%
    \fi
  \fi
}
\newcommand{\lorenzo@warning}[2]{%
  @latex@warning@no@line{you have #1 than #2 pages}%
}
\makeatother
\mainpagerange{10}{40}
\begin{document}
\mainmatter
% this generates pages 1 and 2 (blank)
\chapter{Test 1}\lipsum[1]
% this generates pages from 3 to 10 (no blank)
\chapter{Test 2}\lipsum[1-40]
% this generates pages from 11 to 41
\chapter{Test 3}\lipsum[1-100]\lipsum[1-81]
% this generates page 43 (and blank 44 with \backmatter)
\chapter{Test 4}\lipsum[1]
%\backmatter
\end{document}

Try the various combinations. In this case I get

LaTeX Warning: WARNING: you have more than 40 pages.

No warning if I remove the last chapter, notwithstanding that the total number of pages is 41 (the second page in the first chapter is blank).

You may want to do

\renewcommand{\cleardoublepage}{%
  \clearpage
  \if@twoside
    \ifodd\c@page
    \else
      \stepcounter{lorenzo@skippage}%
      \hbox{}%
      \thispagestyle{empty}%
      \newpage
      \if@twocolumn
        \hbox{}\newpage
      \fi
    \fi
  \fi
}

in order to have really empty pages.

Count pages & warning

1 Answers1