General ⇒ Space after Command

[Laurentius]

How does \& prevent the space following it from being swallowed?

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\documentclass{article}

\newcommand\scil{sc.}

\begin{document}

Cats \& dogs.

Pigs \scil cops.

% \show\& says \& = \char"26, but

Cats \char"26 dogs.

\end{document}

Can that be done for other commands as well?

[Johannes_B]

The simplest thing would be to add an empty group \&{}.

If this doesn't help you, please provide a minimal working example.


Best regards
Johannes

[Laurentius]

I already did provide one. \&{} is unnecessary, since \& already has the desired behaviour.

Code: Select all

\documentclass{article}

\def\scil{sc.}

\begin{document}

Cats \& dogs.

Cats \&c.

Fair \scil square. % This should have a space

(Fair \scil) square. % This should still be possible

\end{document}

My problem is that I don't know how to produce this for other commands (without using the package xspace).

[cgnieder]

This is normal TeX behaviour: control sequence names can either consist of arbitrarily many letters (that is characters with category code 11) or of one character with another category code. Since TeX can only determine where a control sequence name of letters ends by the first non-letter you need some marker to tell TeX where the name ends. This can be a space, a opening brace, a punctuation mark... On the other hand control sequences whose name is made of one non-letter can't be longer than the one character so it does not need any marker to tell TeX where it ends. The first sort have one problem: what if you want the control sequence immediately followed by letters? Say, you have the control sequence \foo followed by the letters bar:

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\foobar

This can't work since it would be interpreted as the control sequence \foobar

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\foo{}bar

Not ideal: it would break possible ligatures. Hence the solution as it is: trailing spaces are ignored.

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\foo bar

That's just how it is. The usual way if one does not want that the space is ignored is one of the two following ways:

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\foo\ bar or \foo{} bar

With a non-letter control sequence the problem doesn't exist as

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\&bar

will work nicely.

That being said: there is xspace.

Regards

[Laurentius]

Thanks, Clemens! I've been puzzled by this for a long time.

Beste Gruesze,
Lorenz