Mrthfx

Apologies for the rather general title, while trying to sort out a very specific problem:

I'm trying to enhance the framework that Alan Munn provided here
to represent naturally occurring discourse (with some extras, omitted here), with code from this answer by frougon.
The point of it all is to have a mechanism for Alan's code (which uses the expex package) to not print repeated labels of speakers. I thought I would be able to integrate the two solutions, yet, with increased complexity, somehow along the way I managed to screw it up and for the life of me I can't figure out what's wrong.

This is as minimal a WE as it gets:

% !TEX TS-program = xelatexmk

RequirePackage{filecontents}



begin{filecontents}{discourse.sty}

NeedsTeXFormat{LaTeX2e}

ProvidesPackage{discourse}



RequirePackage[user,savepos]{zref}

RequirePackage{expex}

newcounter{linenum}

newlength{largestspkr}

newlength{largestnum}

newcommand{deflargestlabel}[2][99]{

settowidth{largestnum}{#1}

settowidth{largestspkr}{~#2}}

deflargestlabel[999]{speaker~99}



RequirePackage{perpage}



newcounter{spkrcounter}

    MakePerPage{spkrcounter}



newenvironment{discourseenv}{%

  setcounter{linenum}{0}%

  setcounter{spkrcounter}{0}%

  ignorespaces

}{%

  parignorespacesafterend

}



DeclareOption{skiprepetitions}{%

  AtBeginDocument{letdiscourse@printdiscourse@print@skip}%

}

DeclareOption{keeprepetitions}{%

  AtBeginDocument{letdiscourse@printdiscourse@print@keep}%

}

ExecuteOptions{skiprepetitions}

ProcessOptionsrelax



RequirePackage{xifthen}



defdiscourse@storedval{} % create a macro to later store a value in



newcommand{spkr}[1]{%

  % create line numbers:

  refstepcounter{linenum}makebox[largestnum][r]{thelinenum}hspace{1em}

  ifthenelse{isempty{#1}}%

    {makebox[largestspkr][l]{}}% if empty > empty box

    {% If this is the first stepcounter{spkrcounter} executed since the current

     % page was started, this sets 'spkrcounter' to 1.

     stepcounter{spkrcounter}% 

     discourse@print{#1}%

     defdiscourse@storedval{#1}%

    }%

}



defdiscourse@print@skip#1{%

  ifthenelse{cnttest{value{spkrcounter}}>{1}AND

        equal{#1}{discourse@storedval}}%

   {makebox[largestspkr][l]{}}% if repeated > empty box

   {makebox[largestspkr][l]{#1:}}%

}

defdiscourse@print@keep#1{makebox[largestspkr][l]{#1:}}



end{filecontents}



documentclass{article}

usepackage{discourse}



begin{document}



Here it works:



spkr{A} OK



spkr{A} OK



spkr{B} OK



spkr{A} OK



vbox{}

Here too in the environment:



begin{discourseenv}



spkr{A} OK



spkr{A} OK



spkr{B} OK



end{discourseenv}



vbox{}

But in combination with expex it screws up:



begin{discourseenv}



ex[exno=spkr{A}, exnoformat=X] OK (prints A) xe



ex[exno=spkr{A}, exnoformat=X] OK (empty) xe



ex[exno=spkr{B}, exnoformat=X] OK (prints B) xe



ex[exno=spkr{A}, exnoformat=X] OK (empty) xe



ex[exno=spkr{B}, exnoformat=X] OK (prints B) xe



end{discourseenv}



begin{discourseenv}



ex[exno=spkr{B}, exnoformat=X] OK (prints B) xe



newpage



ex[exno=spkr{B}, exnoformat=X] OK (prints B) xe



ex[exno=spkr{B}, exnoformat=X] This one should be empty xe



ex[exno=spkr{B}, exnoformat=X] This one should be empty xe



ex[exno=spkr{A}, exnoformat=X] This one should print A  xe



ex[exno=spkr{A}, exnoformat=X] OK (empty) xe



end{discourseenv}



end{document} 

It works as expected on the first couple of instances of the spkr macro, but on the next page it behaves weirdly. Anyone able to spot what's wrong?