Btukfyl

Beamer's 'lecture' command has been a great way for me to have all my lecture notes in one document, but typeset only the segments that I need for any given day/week of class. Ultimately I would like to try and adapt this command to other document classes (currently it is very embedded in the 'beamer' class).

I would consider myself an advanced TeX user, but a novice when it comes to advanced programming (I've put together a few of my own `class' files, but nothing too advanced).

Here's what I found in 'beamerbasesection.sty':

%

% Lecture Definitions

%

newififbeamer@inlecture

beamer@inlecturetrue



newcommand{beamer@if@in@clist@TF}[2]{%

  defbeamer@if@in@clist@aux##1,#2,{}%

  expandafterexpandafterexpandafterifx

    expandafterexpandafterexpandafter@nil

    expandafterbeamer@if@in@clist@auxexpandafter,#1,{}{},#2,@nil

    expandafter@secondoftwo

  else

    expandafter@firstoftwo

  fi

}



newcounter{lecture}

renewcommandthelecture{@arabicc@lecture}

letinsertlecturenumber=thelecture

newrobustcmd*lecture{@dblargbeamer@lecture}

longdefbeamer@lecture[#1]#2#3{%

  beamer@savemode

  mode<all>%

  refstepcounter{lecture}%

  defbeamer@currentlecturelabel{#3}%

  @onelevel@sanitizebeamer@currentlecturelabel

  defbeamer@lecturename{#2}%

  defbeamer@shortlecturename{#1}%

  ifxbeamer@onlylecture@empty

  else

    expandafterbeamer@if@in@clist@TFexpandafterbeamer@onlylecture

      expandafter{beamer@currentlecturelabel}%

      {beamer@inlecturetrue}%

      {beamer@inlecturefalse}%

  fi

  beamer@atbeginlecture

  beamer@resumemode

}

So how does this command work its magic? When I type includeonlylecture{foo}, how does it know to grab only the text after lecture{}{foo} and before the next 'lecture' command? Thanks for any insight you can give!

Just for completeness I've included a minimal working example:

documentclass{beamer}



includeonlylecture{foo}



begin{document}

lecture{}{notfoo1}

begin{frame}

frametitle{Text1}

This frame won't show.

end{frame}





lecture{}{foo}

begin{frame}

frametitle{Hello, World!}

Greetings.

end{frame}





lecture{}{notfoo2}

begin{frame}

frametitle{Text2}

This frame won't show either.

end{frame}

end{document}