Remove space after command

Question

To simplify some text I created some commands. One command has no arguments. It uses math mode but is used inside normal text. I would like to remove any trailing space between the command and following text. This will allow me to simply the call such as \cmd sometext instead of {\cmd}sometext. Is there any way to create a negative space?

Answer 1

If your command is truly a single macro without arguments, i.e. \cmd, then it gobbles spaces written after it anyway. To ensure that any command will absorb following spaces, just make the last thing to appear in it \ignorespaces, which causes TeX to consciously discard space characters until the first non-space appears.

By the way: {\cmd}sometext does not do what you think, if part of the action of \cmd is to make definitions of some kind. Those definitions will be discarded inside the group created by {...} unless you make them global. The way to have two items bump up against each other but be parsed separately is to write \cmd{}sometext. However, as I said, \cmd itself will eat spaces no matter how you define it.

Answer 2

That is the default behavior as the output of \foo bar shows below (the first line). To introduce negative horizontal space you could use \kern:

\documentclass{article}
\newcommand*{\foo}{foo}%
\newcommand*{\fooWithKern}{foo\kern-1ex}%
\begin{document}
\foo bar

\fooWithKern bar
\end{document}