#10 New slide selection feature

[Vladimir V Kisil]

Hi,

First of all thanks for developing TeXpower which I am
enjoying very much.

I wish to propose another slide-selection mechanism.
The present one (based on the slide numbers) is rather
fragile in the case some slides are
inserted/deleted/rearranged.

I propose to have a command like

\tagslide{foo,foo1,foo2}

to be put inside slide enveronment. As result tags foo,
foo1, foo2 will be associated to the present slide.
Other slide enveronments may be tagged by some of these
or different tags.

If the preambula contains the command

\selecttag{foo1}

then the output will contain only slides which were
tagged by foo1.

Presently I am achieving this behaviour by following
set of commands in my custom style file:

\newcommand{\selecttag}{everything}
\newcommand{\everything}{}
\makeatletter
\let\oldos@test=\os@test
\gdef\os@test{\oldos@test

\expandafter\ifx\csname\selecttag\endcsname\relax\@testfalse\else\@testtrue\fi}
\let\oldos@test\relax
\gdef\tagslide#1{\@for\@tempx:=#1\do{\expandafter\def\csname\@tempx\endcsname{}}}
\makeatother