[XeTeX] Extra trailing space in IPA font with xltxtra

[Philip Taylor (Webmaster, Ret'd)]

Ross Moore wrote:

> However, I'm not convinced that this is the most robust way
> of tackling this issue.
> Should it be localised to just when  linguex  is used?
>
>
> Here is how I think this kind of interaction-between-packages
> specific kind of issue should be solved. What do you think?
>
>>>> \def\implementTIPAtextx#1{#1\egroup}
>>>> \def\implementTIPAtextxx#1{\endlinechar=-1 \scantokens{#1}\egroup}
>>>> \AtBeginDocument{\let\textipa\implementTIPAtext}
>>>> \expandafter\ifx\csname scantokens\endcsname\relax
>>>> \else
>>>>   \AtBeginDocument{\@ifpackageloaded{linguex}{%
>>>>    \let\implementTIPAtextx\implementTIPAtextxx}}
>>>> \fi
>
>
> If everyone agrees, this is how the next subversion
> of Xunicode will deal with this.

Not convinced this is optimal.  Whilst linguex may be
unusual in grabbing everything up to the next \par as
#1 to \ex., there can be no guarantee that it is the
only package so to do.  Therefore, rather than risk
having to add additional packages to the

	\@ifpackageloaded {linguex}

test, might it not be better to simply use \scantokens
regardless ? As to whether eTeX is buggy in its
implementation of \scantokens, I would argue not :
the documentation clearly says --

> \scantokens,
>     when followed by a <general text>, decomposes the
 >    <balanced text> of the <general text> into the
 >     corresponding sequence of characters as if the
 >    <balanced text> were written unexpanded to a file;
 >     it then uses TeX's \input mechanism to re-process
 >     these characters under the current \catcode régime.
 >     As the \input mechanism is used, even hex notation
 >    (^^xy) will be re-interpreted. Parentheses and a single
 >     space representing the pseudo-file will be displayed
 >     if \tracingscantokens (q.v.) is positive and non-zero.

where the key part is "uses TeX's \input mechanism"; if it
is unclear why this yields a final space, please try
the following :

File "A" : pre\input B\relax post\end
File "B" : middle

Philip Taylor