Subscript and superscript in text mode

I often need to write various thing in subscript and superscript which have nothing to do with maths so I don't want to have them written in math mode. For LaTeX users there is no easy way to write subscript and superscript in text mode.
XeTeX, however, has prepared some macros for this. Assuming you have \usepackage{xltxtra} in the preamble, you can use the commands

\textsubscript{}
\textsuperscript{}

if you want something like C_2 you write C\textsubscript{2}. Of course if you use this a lot, it is much more convenient two write some shorthand command to use instead these long ones.

Those of you who still write in LaTeX may find a solution here.

First gloss line in italics (gb4e)

The solution is in the gb4e manual on page 7:

% first gloss line in italics:
\let\eachwordone=\it

Block comment

If you need to comment out a block of text, use the verbatim package. That provides the comment environment:

\begin{comment}
…
\end{comment}

Line spacing in tables

If you need more space between the lines in a table use the array package and put the following line somewhere between \begin{table} and \begin{tabular}

\setlength{\extrarowheight}{length}

Instead of “length” you write the desired space, e.g. “3pt”

Verbatim text as command argument

In my dissertation I will refer to the N|uu text corpus. The corpus has reference units which are called e.g. NA071112-01_E.008. I thought all the references to the text corpus are markup-worthy entities so I needed a command like \ru (short for reference unit) to markup those references with it like this: \ru{NA071112-01_E.008}.

As you know, the underscore “_” is a special character used in math mode for subscript. So it is not allowed to occur as a part of some string. I did not want to write \ru{NA071112-01\_E.008} instead. I looked for a way to feed commands verbatim text arguments.

I stumbled upon the fancyvrb package, which looks really promising for this, especially in the documentation on p. 17 where some magic aftersave is used. But the aftersave parameter is heavily underdocumented there. That’s just my luck. I could not find out what aftersave actually does and if it will enable me to write someting like \ru{NA071112-01_E.008}.

I then sought help at comp.text.tex (topic: fancyvrb problems) and Enrico Gregorio was so kind to write me this TeX code:

\def\ruspeciallist{\do\_} % add the special characters you need with "\do\X" (X is the characater)

\def\rucatcodes{\def\do##1{\catcode`##1=12 }\ruspeciallist}
\newbox\rubox
\def\ru{\afterassignment\dorusetup\let\next= }
\def\dorusetup{\setbox\rubox=\hbox\bgroup
\rucatcodes \aftergroup\dorufinish}
\def\dorufinish{\box\rubox}

An extensively commented version is also there.

In the last line between “\dorufinish{” and “\box\rubox}” come all the commands you want to apply the the argument of \ru. BUT:

Enrico: “A limit of this approach is that the string is never read as an
argument, so that it is not available for, say, writing an index
entry: we have it only in typeset form, inside the box.”

Ok, this certainly is a nice piece of code but it does not essentially allow verbatim text to be an argument of a command. It is just a work-around to get that verbatim text typeset somehow (and that's what I have originally asked for in the newsgroup). So, in that sense, verbatim text as argument still is an open issue.

Enrico — after I told him I actually may want to index that stuff — suggested a much simpler and elegant solution for my particular needs.

Anyway, if anybody of you readers finds out how to use the aftersave of fancyvrb package do inform me in the comments to this post. I’d really like to know. I think it has something to do with TeX’s \expandafter.