General ⇒ About the symbol @ | learn to write LaTeX package

[vita001]

Hi,
The symbol @ is used everywhere in .cls files. But I cannot find a documentation about its usage. Anyone can give me some links to the documentation? I also want to learn how to write a Latex package. Which books/links are good starting points?
Thanks.

[Stefan Kottwitz]

Hi,

The symbol @ is used everywhere in .cls files. But I cannot find a documentation about its usage.

the character @ is used in names of internal commands, which are not intended to be used by document authors. Such commands may be changed, they can be even considered as unsupported.

Since commands with an @ in the name cannot be directly used within documents, it's a kind of protection to add @ to internal macro names, that's why class files use it.

Anyone can give me some links to the documentation? I also want to learn how to write a Latex package. Which books/links are good starting points?

A good starting point is the LaTeX2ε for class and package writers aka clsguide. Have a look at 2.4 Command names.

Stefan

[vita001]

I read the "latex for class and package writers". It's a good but short introduction. I try to look at some .cls files to better understand how latex packages/classes work.

I encountered the follow code
\advance\textwidth-\sectionwidth

I try to look up what \advance does, but I get very little from the internet. TeX has \advance command but it is called by different format ( which is, \advance<name> by <number><unit>) so I guess Latex redefines the command somewhere but I could not find the place which documents this command.

Are there any places for complete reference of internal latex command used by the package/class writers? I googled and got some links like macro2e http://tex.stackexchange.com/questions/ ... l-commands. But the list seems incomplete. Any suggestions? Thanks.

[Stefan Kottwitz]

You could read in The Documented LaTeX2e Sources. It should already be included your TeX distribution with the file name source2e.pdf.

I usually open it at the command prompt by

Code: Select all

texdoc source2e

Stefan