On 11/21/20 11:04 AM, Wolfgang Schuster wrote:
To check whether a stretch or shrink value is set LMTX takes a look at the next character (p, P, m or M) before it makes a decision, when you have now a word after \hskip which start with one of these characters (e.g. Materiam) you trigger the scanner which fails because it didn't find a keyword. To avoid such problems always add \relax after the last value of \hskip, this is even explained in one of the exercises in the TeXbook.
Thank you Wolfgang, now it all makes sense. I will relax more and dust off my copy of the TeXbook. I used to read small chapters in the tramway on my way to the university, but with the lockdown, I didn't have this opportunity. Nah, just kidding, I haven't looked at it in a long time. Thomas