document-classesdocumentclass-writingpackage-writingpackages
Are there general rules for when to create a document class vs. creating a package to customize LaTeX? Does one have benefits over the other?
My specific need is to create a customized page layout, but I'm interested in the general response to this question as well.
I did quite a bit of poking around for an answer to this, but surprisingly couldn't find much information.
You seem to confuse some things and terms here.
You should never edit existing class or package files, at least not without changing the file name. This is a major point of the LPPL license. If you want to customize a class rename it and make your changes there. Even better would be to load the existing class using \LoadClass or \LoadClassWithOptions and then (re-)define all macros and settings the way you want it.
Every class files is located in <name>.cls file, if it is an "original" class or a derived class (i.e. based on another class). There are no "templates" in LaTeX. People keep using this expression and keep confusing it with class files.
texMemo is a dedicated class for writing memos. Here's an example:
\documentclass[a4paper,12pt]{texMemo}
\usepackage{graphicx}
\memoto{Donald E. Knuth}
\memofrom{TeX Stack Exchange}
\memosubject{Your honorary membership to TeX.SX}
\memodate{\today}
\logo{\includegraphics[width=0.3\textwidth]{texsx}}
\begin{document}
\maketitle
\noindent
We all are glad to welcome you as a honorary member of our site.
\end{document}
Download, documentation and examples are here:
Since memos are very similar to letters, you could use a letter class and customize it as desired. Have a look at the corresponding TeX catalogue section for a list of classes and packages:
Best Answer
Maybe one could say a package is for extending possibilities, a class is for restricting possibilities.
If you want to add new features which can help users create specific effects in a lot of different document types, a package is for you.
If you want to set sensible defaults and create an optimal environment for efficiently creating documents of a specific type without having to do a lot of customisation, make a class.
There are a lot of fringe cases, of course ;-)