ExSheets includequestions

Question

I have a large file database.tex with a lot of questions and solutions in the format of the ExSheets package. If I include multiple questions with one \includequestions command, the questions are included in the order of there definition in database.tex. So there is no difference between the following two lines

\includequestions[IDs={q1,q2}]{database.tex}
\includequestions[IDs={q2,q1}]{database.tex}

If I want a specific order or the questions I need multiple \includequestions commands:

\includequestions[IDs={q2}]{database.tex}
\includequestions[IDs={q1}]{database.tex}

But database.tex is large and I want to include 6 or more questions in a specific order. Thus, typesetting needs more than 1 minute. Is there a better and faster way?

---

Update: I forgot to mention that I use a custom header for questions and solutions (to keep it easy I only give the code for the header of questions):

...
\begin{question}[ID=q1,subtitle={T1}]
...

\def\loesung{}

\ExplSyntaxOn  
\DeclareInstance{exsheets-heading}{myhead}{default}{
  number-post-code = {\hspace{1em}\textbf{\tl_use:N \l__exsheets_questions_subtitle_tl}~%
  \ifdef{\loesung}{\color{blue}\tiny(\texttt{\tl_use:N \l__exsheets_questions_id_tl})}{}
  } ,
  join = {
    title[r,B]number[l,B](.333em,0pt)
  } ,
  attach = {
    main[l,vc]title[l,vc](0pt,0pt)
  }
}
\ExplSyntaxOff

\RenewQuSolPair
  {question}[][headings=myhead]
  {solution}[][headings=myhead]

If I use the answer from @cgnieder, I get:

Answer 1

Here is a possible workaround: the idea is to include the questions but hide them, i.e., print nothing. exsheets question properties then allow to print the needed parts selectively.

Caution: The code below is a hack that uses internal functions so it may break in future versions of exsheets...

In order to hide the questions when included a few hacks are needed:

\cs_new_protected:Npn \hidequestions
  {
    \keys_set:nn {exsheets}
      {
        headings=blank ,
        skip-below=0pt
      }
    \cs_set:Npn \__exsheets_save_and_print_question_body:n ##1
      { \exsheets_set_question_properties:n { question-body = {##1} } }
    \cs_set_eq:NN \exsheets_h_or_vspace:N \use_none:n
  }

A little bit more work is needed to print the questions (but no use of internal functions this time so the following is safe to use). The idea is to map over a comma separated list of IDs and print a question for each containing the question body of the original question for each ID. The questions must get 0 as value for points and bonus points if no points are given to avoid errors which means we need to check them first.

\tl_new:N \l_exsheets_this_question_points_tl
\tl_new:N \l_exsheets_this_question_bonus_tl

\cs_new_protected:Npn \printquestions #1
  {%
    \clist_map_inline:nn {#1}
      {
        % check if points are given or unknown,
        % if yes feed `0' to the heading:
        \prop_get:NnNF \g__exsheets_question_property_points_prop
          {##1}
          \l_exsheets_this_question_points_tl
          { \tl_set:Nn \l_exsheets_this_question_points_tl {0} }
        % same for bonus points
        \prop_get:cnNF {g__exsheets_question_property_bonus-points_prop}
          {##1}
          \l_exsheets_this_question_bonus_tl
          { \tl_set:Nn \l_exsheets_this_question_bonus_tl {0} }
        % typeset the question:
        \begin{question}{
            \l_exsheets_this_question_points_tl +
            \l_exsheets_this_question_bonus_tl
          }
          \exsheets_get_question_property:nn {question-body} {##1}
        \end{question}
      }
  }

With the above defined functions and a file exercises.tex which contains

\begin{question}[ID=q1]
  Q1
\end{question}
\begin{question}[ID=q2]
  Q2
\end{question}
\begin{question}[ID=q3]
  Q3
\end{question}

the document body

\begin{document}

\printquestions{q3,q1}

\hidequestions
\includequestions{exercises.tex}

\end{document}

gives

A warning: This approach has some drawbacks

• most notably: \totalpoints and friends will count the points of the questions two times: once when included and the second time when printed.
• \ForEachQuestion will loop over the questions twice for the same reason.
• others I didn't think of, yet, ...

The complete code:

\documentclass{article}
\usepackage{exsheets}

\usepackage{filecontents}
\begin{filecontents*}{exercises.tex}
\begin{question}[ID=q1]
  Q1
\end{question}
\begin{question}[ID=q2]
  Q2
\end{question}
\begin{question}[ID=q3]
  Q3
\end{question}
\end{filecontents*}

\DeclareInstance{exsheets-heading}{blank}{default}{
  inline = true ,
  above = 0pt ,
  below = 0pt ,
}

\ExplSyntaxOn
\cs_new_protected:Npn \hidequestions
  {
    \keys_set:nn {exsheets}
      {
        headings=blank ,
        skip-below=0pt
      }
    \cs_set:Npn \__exsheets_save_and_print_question_body:n ##1
      { \exsheets_set_question_properties:n { question-body = {##1} } }
    \cs_set_eq:NN \exsheets_h_or_vspace:N \use_none:n
  }

\tl_new:N \l_exsheets_this_question_points_tl
\tl_new:N \l_exsheets_this_question_bonus_tl

\cs_new_protected:Npn \printquestions #1
  {%
    \clist_map_inline:nn {#1}
      {
        % check if points are given or unknown, if yes feed `0' to the heading:
        \prop_get:NnNF \g__exsheets_question_property_points_prop
          {##1}
          \l_exsheets_this_question_points_tl
          { \tl_set:Nn \l_exsheets_this_question_points_tl {0} }
        % same for bonus points
        \prop_get:cnNF {g__exsheets_question_property_bonus-points_prop}
          {##1}
          \l_exsheets_this_question_bonus_tl
          { \tl_set:Nn \l_exsheets_this_question_bonus_tl {0} }
        \begin{question}{
            \l_exsheets_this_question_points_tl+\l_exsheets_this_question_bonus_tl
          }
          \exsheets_get_question_property:nn {question-body} {##1}
        \end{question}
      }
  }
\ExplSyntaxOff

\begin{document}

\printquestions{q3,q1}

\hidequestions
\includequestions{exercises.tex}

\end{document}