# [texhax] Constructing a very thin space

Axel E. Retif axel.retif at mac.com
Fri Jul 26 02:04:40 CEST 2013

```On 07/25/2013 06:10 PM, Karl Berry wrote:

> I do not have an example at hand, but without the space after `em', TeX
> will still be reading and expanding tokens after the macro is called (to
> look for the <space> that's supposed to be there).

[...]

> Knuth did not put that final space in the
> definition of \thinspace just for fun (\relax would work too).
>
> It's definitely the best practice to make sure that macros terminate
> their arguments.  Otherwise it's just asking for trouble.