Feedback on LaTeX output usepackage customization

[Patrice Dumas]

Hello,

For LaTeX output, it seems important to allow to customize the
beginning of the preamble, with the documentclass and usepackage.
The remaining of the generated preamble can probably be undone/modified
by LaTeX code in a @latex block appearing in the preamble, before any
formatted content, though some generated code depends on some
\usepackage being emitted.


The generated documentclass/usepackage preamble is the following:

First a constant part

 \documentclass{book}
 \usepackage{amsfonts}
 \usepackage{amsmath}
 \usepackage[gen]{eurosym}
 \usepackage{textcomp}
 \usepackage{graphicx}
 \usepackage{etoolbox}
 \usepackage{titleps}

Then a part that depends on the document encoding, with, for UTF-8

 \usepackage[utf8]{inputenc}
 \usepackage[T1]{fontenc}

Then some \usepackage depending on the Texinfo @-commands used in the
document.  For example

 \usepackage{imakeidx}    (presence of indices)
 \usepackage{needspace}   (@need)
 \usepackage{array}    (@multitable)
 \usepackage{embrac}    (@deffn, @defun...)
 \usepackage{expl3}     (needed by embrac related code)
 \usepackage{tabularx}   (@def*)
 \usepackage[framemethod=tikz]{mdframed}   (@cartouche)
 ...

Lastly

 \usepackage[hidelinks]{hyperref}


My plan is to add 
* a customization variable that would replace the first two blocks,
  (from \documentclass{book} to \usepackage[T1]{fontenc}), named
  CLASS_BEGIN_USEPACKAGE
* a customization variable that would replace the remaining (dynamically
  determined usepackages and \usepackage[hidelinks]{hyperref}), named
  END_USEPACKAGE


What do you think?  Is it the right level for customization?  Would that
be easy to use?

-- 
Pat