[Therion] The purpose of \thfb

[Tarquin Wilton-Jones]

Why do I always do this to myself? Send a mail, then work out the answer...

> But I have no idea why that works, and was hoping someone could explain
> to me:
> 1. What is \thfb ?

thTMPDIR\th_enc.tex

\def\mainfont{\thfb}

It is telling it to use TeX's "mainfont". There are also some others
defined in that file, like \rm which can be used instead of \thfb

> 2. Why does it need that, and not a space?

Because it used to default to using the mainfont, now it defaults to
using no font.

> 3. How come it works without the whitespace, when plaintext could be
> anything, and that could construct a btex like:
> \thframed {\thnormalsize\thfbfoo}
> I would have expected \thfbfoo to be a command, but it seems to know
> that it is "\thfb" and "foo", not a single command.

Because "foo" was numbers. \thfb123 = "\thfb" and "123", while that is
not the case for letters. With letters, they are all assumed to be part
of the command. Therefore it needs a space so it knows where the command
name ends.

> 4. Is there a better way to construct a btex "string" that can be used
> to create a p_label.urt piece of text that can work with the
> p_label_mode_passageheight style?

Leaving this question open, because I don't have an answer.