[texhax] Weirder and weirder

[Uwe Lueck]

Richard Davies <richard at tollyboy.demon.co.uk>, 17.08.2010 01:32:21
>On 16/08/10 22:27, Michael Doob wrote:
>> On Monday 16 August 2010 4:14 pm, Michael Barr wrote:
>>> In connection with the question I raised about revtex a couple days ago, I
>>> would ask texhaxxers to explain the following behaviour, which has nothing
>>> to do with revtex.  First, examine the following and try to predict the
>>> results.  Then run it and see the actual ones.
>>>
>>> \documentclass{article}
>>> \showthe\textfont0
>>> \setbox0=\hbox{x}
>>> \showthe\textfont0
>>> \showthe\textfont2
>>> \setbox0=\hbox{$x$}
>>> \showthe\textfont2
>>> \showthe\textfont0
>>> \begin{document}
>>> \end{document}
>
>Seems to compile OK on my box.
>log file looks normal.
>Produces no pages of output I guess because it is a completely empty 
>document.

I think the OP is still wondering at which .tex lines TeX replaces \nullfont by the font acting in typesetting. I didn't remember well myself, but the OP's .log indicates that the \textfont's (TeXbook p. 153) are chosen at the first $, which triggers LaTeX's \check at mathfonts.

Cheers, 

    Uwe.