Joey McCollum via ntg-context schrieb am 10.10.2021 um 05:42:
> The test using \removepunctuation that you provided does what it 
> should be doing (it produces 6 instances of "test-test" with the 
> intervening punctuation mark in each case removed), but it doesn't do 
> what I'm trying to do in the MWE above. I'm trying to take certain 
> punctuation marks that follow the \autopuncttest macro and place them 
> before it instead. Looking at the typo-chr .lua and .mkiv files, I see 
> that there are \pushpunctuation and \poppunctuationmethods in addition 
> to the \removepunctuation method. These might be useful for this 
> purpose, but in any case, I still have to check if the trailing 
> character is one of the characters in a specified set/string, and this 
> is where the error is arising.

Add \protected (or \unexpanded) to your command definition.

\startbtxrenderingdefinitions[myspec]
\protected\def\autopuncttest#1#2%
   {\removeunwantedspaces%
    \doifinstring{#2}{,.!?;:}{#2}%
    \footnote{#1}%
    \doifnotinstring{#2}{,.!?;:}{#2}}
\stopbtxrenderingdefinitions

Wolfgang