[cess11]

No, there's a specificity to "name" and "group" that makes them similar, which is one part of why I settled on this example. The other is that I expected the recipient to have experience with regex and find the example dumb, confirming my position that one can very well demand a basic knowledge of the tool that isn't immediately communicated by it.

Like knowledge of the regex language, or having spent ten minutes skimming through the tutorial part of a PDF manual.

In my experience, how to use a manual is a technique more widely understood than regex. Maybe this impression is wrong, I'd welcome something tangible pointing in another direction if it is.

[jfyi]

If it's any consolation, I (some random guy on the internet) would look for naming conventions in the manual if I was given the error "invalid name".