[texhax] spurious space with abbrevs.sty

[Uwe Lück]

Am Freitag, den 28.09.2012, 13:26 +0200 schrieb Ulrike Fischer:
> Am Fri, 28 Sep 2012 10:44:41 +0200 schrieb Herbert Voss:
> 
> > there is a problem with the internal macro \maybe at space@
> > which _always_ inserts a space. However, the package abbrevs
> > loads some other packages which might have change their
> > behaviour.
> 
> I can't see how it could ever have worked: \maybe at space@ uses
> \t at st@ic which sets \maybe at icfalse. Testing afterwards with
> \if at tempswa doesn't make sense. 

That's it, it works fine with my 2009 LaTeX (Debian TeX Live):

\def \t at st@ic {%
  \expandafter\let\expandafter\reserved at b\expandafter=\reserved at a\relax
  \ifx\reserved at b\@let at token
    \@tempswafalse
    \@break at tfor
  \fi
}

sets \@tempswafalse iff \@let at token is \ifx-equivalent to 
a member of the exception list (which is stored in 
\reserved at a). Previously, there was \@tempswatrue. 
Therefore \if at tempswa is \iftrue and allows a \space iff 
\@let at token is not equivalent to a member of the exception 
list. And as I said, it just works fine.

So they have replaced \@tempswafalse by \maybe at icfalse, 
and actually the 2009 latex.ltx doesn't have an \ifmaybe at ic.

Cheers, 

    Uwe.