@jxf I already know about Hugo Multilingual support, as you can see in this other thread that I myself started last month:
The rest of that website, as far as multilingual goes, is OK now. Only this different (sub)issue was still open for me. I have already got what I wanted with the hack in my previous comment. But I would still like to know if there is a better way to do this, i.e to pass to readFile a file name that is NOT a constant string, but contains a Hugo variable. In bash, I know I could say
readFile "blocks/$LanguagePrefix/main.html"
what is the equivalent go/Hugo syntax to do the same thing? This is what I still don’t know.