Exercises imported don't print when i call a collection

Question

I undertook to build a database of my exercises and to store them, i wrote in subfolders. When needed, i called them with xsim package.

At the moment, the classification acts as follows :

And there are 4 difficulty.tex files at the end. I tried to use tags but was unsuccessful.

To make the call easier in a document and to compile only a part of a document, i've build the two files :

• 5M4_AlgebreFinanciere_CollectDeclaration.tex (in '5M4_AlgebreFinanciere')
• 5M4_AlgebreFinanciere_CollectExercises.tex (also)

So i can (un)comment the import if i don't need to compile those parts.

In those two files, i want to call the corresponding .tex files with commands to make it more flexible if i've to change names, create a new folder,...

Compilation when i write all the files manually works. But when i use something like : \collectexercises{\ExOption_\ExPart_\ExSubPart_\ExDifficulty1} with command defined to make a good path, everything work except that no exercise are printed. Collection seems to be declared in a good way and exercises are collected (see 'Exercises_Generating_Folder').

My question is : Why exercises are printed with path/names properly wrote and are not, although it compiles successfully, when i use \command ?

Here, i reduce the project to a MWE :

Main.tex :

\documentclass[10pt,a4paper]{book}
\usepackage[verbose,clear-aux]{xsim}
\usepackage{import}

\xsimsetup%
{%
    path = {Exercises_Generating_Folder},   %%Avoid flooding of exercises files
}

%%Declaration exercices
\newcommand{\ExOption}{default}
\newcommand{\ExPart}{default}
\newcommand{\ExSubPart}{default}
\newcommand{\ExDifficulty}{Difficulty}

\import{5M4/AlgebreFinanciere/}{5M4_AlgebreFinanciere_CollectDeclaration.tex}

\begin{document}
\chapter{Algebre Financière}
\import{5M4/AlgebreFinanciere/}{5M4_AlgebreFinanciere_CollectExercises.tex}
    \printcollection{5M4_AlgebreFinanciere}
    \printsolutions*[collection=5M4_AlgebreFinanciere]
\end{document}

5M4/AlgebreFinanciere/5M4_AlgebreFinanciere_CollectDeclaration.tex

 %%Set up the commands to implement correctly this file
 \renewcommand{\ExOption}{5M4}
 \renewcommand{\ExPart}{AlgebreFinanciere}
 \renewcommand{\ExSubPart}{default}

 %%Declare Global Collection for the part
 \DeclareExerciseCollection{\ExOption_\ExPart}

 %%Declare a subpart of the Global Collection
 \renewcommand{\ExSubPart}{InteretsSimples}
 \DeclareExerciseCollection{\ExOption_\ExPart_\ExSubPart}    %%To declare Collection{5M4_AlgebreFinanciere_InteretsSimples}
 \DeclareExerciseCollection{\ExOption_\ExPart_\ExSubPart_\ExDifficulty1} %%And   Collection{5M4_AlgebreFinanciere_InteretsSimples_Difficulty1}

5M4/AlgebreFinanciere/5M4_AlgebreFinanciere_CollectExercises.tex

 %%Set up the commands to implement correctly this file
 \renewcommand{\ExOption}{5M4}
 \renewcommand{\ExPart}{AlgebreFinanciere}
 \renewcommand{\ExSubPart}{default}


 \collectexercises{\ExOption_\ExPart}         %%Open Global collection.
  \renewcommand{\ExSubPart}{InteretsSimples}
  \collectexercises{\ExOption_\ExPart_\ExSubPart}      %%Open Global subpart collection.
   \collectexercises{\ExOption_\ExPart_\ExSubPart_\ExDifficulty1} %%Open Global subpart collection for the corresponding difficulty.
    \subimport*{\ExSubPart/}{\ExOption_\ExPart_\ExSubPart_\ExDifficulty1.tex} %%
                   %%Import the files where corresponding exercises are.
                   %%This file is in the folder 'AlgebreFinanciere/InteretsSimples'
   \collectexercisesstop{\ExOption_\ExPart_\ExSubPart_\ExDifficulty1}
  \collectexercisesstop{\ExOption_\ExPart_\ExSubPart}
 \collectexercisesstop{\ExOption_\ExPart}

5M4/AlgebreFinanciere/InteretsSimples/5M4_AlgebreFinanciere_InteretsSimples_Difficulty1.tex

\begin{exercise}
    Can you print me ?
\end{exercise}
\begin{solution}
    No, you can't !
\end{solution}

Thanks for any help or advice !

EDIT : The problem comes from the command \ExOption and \ExPart in collection name. In the .aux file, there are spaces or brackets (if i add them after using commands) in collection name who do not allowed me to call the collection with the proper name. I'm looking for a solution to make these commands usable.

Answer 1

The question is solved in this post.

The problem came from the usage of \ExOption and ExPart who did not expand when i call them in \DeclareExerciseCollection{\ExOption_\ExPart} and in \collectexercises{\ExOption_\ExPart}. Tracked by looking the .aux files where the collection was declared with the following name : {collection:\ExOption _\ExPart }{}

So i wasn't able to call the collection to print it in my document with a wrong name.

Thanks to David Carlisle and Frougon for their help to expand the command.