Argthtjtr

Consider this script:

documentclass{report}

usepackage{ifthen}

newcommand{thesissize}{SHORT}

begin{document}

   setcounter{page}{

    %3

    ifthenelse{

    equal{thesissize}{SHORT}

    }{3}{2}

  }

  hey

end{document}

Compiling this script gives the error:

! Missing number, treated as zero.

I suspect that this is due to ifthenelse not being evaluated at the time of executing setcounter. How do I solve this?

you can't use ifthenelse inside setcounter. Change the order:

documentclass{report}

usepackage{ifthen}

newcommand{thesissize}{SHORT}

begin{document}

   ifthenelse{equal{thesissize}{SHORT}}

    {setcounter{page}{3}}{setcounter{page}{2}}





  hey

end{document}

Expandable tests are possible with expl3 and etoolbox. For both you should store the reference text in a command:

documentclass{report}

usepackage{expl3,etoolbox}

newcommand{thesissize}{SHORT}

newcommand{shortsize}{SHORT}



begin{document}

ExplSyntaxOn

setcounter{page}{tl_if_eq:NNTFthesissizeshortsize{3}{2}}

ExplSyntaxOff



setcounter{page}{ifdefequal{thesissize}{shortsize}{3}{2}}



  hey

end{document}

Another version of a string comparison using the pdfTeX macro pdfstrcmp. The following uses the pdftexcmds package to make it available to all engines under the same name:

documentclass{article}



usepackage{pdftexcmds}

makeatletter

newcommandifstreq[2]

  {%

    ifnumpdf@strcmp{#1}{#2}=0

  }

makeatother



newcommandthesissize{SHORT}



begin{document}

setcounter{page}{ifstreq{thesissize}{SHORT}3else2fi}

hey

end{document}

If a LaTeX syntax is preferred one can use

documentclass{article}



usepackage{pdftexcmds}

makeatletter

newcommandifstreq[2]

  {%

    ifnumpdf@strcmp{#1}{#2}=0

      expandafter@secondofthree

    fi

    @secondoftwo

  }

providecommand@secondofthree[3]{#2}

makeatother



newcommandthesissize{SHORT}



begin{document}

setcounter{page}{ifstreq{thesissize}{SHORT}{3}{2}}

hey

end{document}

No packages.

documentclass{report}

newcommand{thesissize}{SHORT}

begin{document}



newcommandtmp{SHORT}

ifxtmpthesissizerelaxsetcounter{page}{3}elsesetcounter{page}{2}fi



thepage



renewcommandtmp{NOT SHORT}

ifxtmpthesissizerelaxsetcounter{page}{3}elsesetcounter{page}{2}fi



thepage

end{document}

The expandable version:

documentclass{report}

newcommand{thesissize}{SHORT}

begin{document}



newcommandtmp{SHORT}

setcounter{page}{ifxtmpthesissize3else2fi}



thepage



renewcommandtmp{NOT SHORT}

setcounter{page}{ifxtmpthesissize3else2fi}



thepage

end{document}