.. _casengine:

========================
CASengine
========================

.. highlight:: latex


The program, together with a larva of documentation, is at 
https://github.com/dlfer/casengine


It is worth considering it for authoring `MOODLE <https://www.moodle.org>`_  questions.  
For authoring multiple choice questions in LaTeX, I suggest using just ``mcq.py``. 
For open questions, on the other hand, ``casengine.py`` may more not that unuseful.

For example, consider the following example file::


    %===================================================================
    \documentclass[twoside,a4paper,leqno]{article}
    %===================================================================
    \usepackage{mathpazo} % I like it.
    \usepackage[sol,doexe]{mcq} 
    \usepackage{polyglossia}
    \setdefaultlanguage{english} %% it needs to be *after* mcq.
    
    \usepackage{casengine}
    
    %===================================================================
    \begin{document}
    
    \begin{esercizi*}{}
    
    \begin{exe}
    \begin{varianti}
    \begin{symfor}{q}{range(2,6)}
    \begin{symfor}{x}{cos(t); sin(t); exp(t); t**2 - 2 * t}
    \symexec{g=x+q*t}
    \symexec{gp=Derivative(expand(g))}
    \varitem 
    Compute $\displaystyle \sym{gp}$.
    \blank{$\sym{simplify(gp.doit())}$}
    \end{symfor}
    \end{symfor}
    \end{varianti}
    \end{exe}
    
    
    \end{esercizi*}
    
    \end{document}


Using the ``casengine.py`` one obtains an expanded file, with all exercises (and solutions), as in 
the :download:`output file <soft/exam_out.pdf>`. How to produce the 16 related 
There are two nested for cycles, with 4 iterations each: hence 16 varied questions. 

The GIFT output, produced by ``mcq.py`` is the following::


    // [Var. 1]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(2 t + \\cos\{\\left (t \\right )\}\\right)$.
    {}
    
    // [Var. 2]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(2 t + \\sin\{\\left (t \\right )\}\\right)$.
    {}
    
    // [Var. 3]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(2 t + e^\{t\}\\right)$.
    {}
    
    // [Var. 4]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\} t^\{2\}$.
    {}
    
    // [Var. 5]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(3 t + \\cos\{\\left (t \\right )\}\\right)$.
    {}
    
    // [Var. 6]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(3 t + \\sin\{\\left (t \\right )\}\\right)$.
    {}
    
    // [Var. 7]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(3 t + e^\{t\}\\right)$.
    {}
    
    // [Var. 8]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(t^\{2\} + t\\right)$.
    {}
    
    // [Var. 9]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(4 t + \\cos\{\\left (t \\right )\}\\right)$.
    {}
    
    // [Var. 10]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(4 t + \\sin\{\\left (t \\right )\}\\right)$.
    {}
    
    // [Var. 11]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(4 t + e^\{t\}\\right)$.
    {}
    
    // [Var. 12]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(t^\{2\} + 2 t\\right)$.
    {}
    
    // [Var. 13]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(5 t + \\cos\{\\left (t \\right )\}\\right)$.
    {}
    
    // [Var. 14]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(5 t + \\sin\{\\left (t \\right )\}\\right)$.
    {}
    
    // [Var. 15]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(5 t + e^\{t\}\\right)$.
    {}
    
    // [Var. 16]
    [html]Compute $\\displaystyle \\frac\{d\}\{d t\}\\left(t^\{2\} + 3 t\\right)$.
    {}


If one does not have a moodle installation with mathjax, or just prefers to handle PDF files,
do as follows.

First generate all permutations with ``mcq.py`` (and the ``doexe`` option). This will produce 
a nice ``exam_out_exam.pdf``. Use then ``qpdf`` to split the file (renaming it if necessary)
and shuffle the result as needed:: 

    $ qpdf --split-pages=4 exam_out_exam.pdf output.pdf


It is not really a stable piece of software, but can leverage all Computer
Algebra Systems to author question banks. It is similar to a static site generator (such as
hugo, jeckyll, ...) compared to a dynamic CMS (which in moodle assessments might be 
for example the  `STACK system <https://moodle.org/plugins/qtype_stack>`_.