bug report, or am I doing something wrong?



I think that you are free to define _ as a new syntactic operator using
syntax extension.  You can then use it as much as you like, as long as you
do not conflict with other uses,  like a separator between words in a name
like Chris_Sangwin.

As for making it part of maxima,  I vote no.  The world has had 31 years
to adopt this convention of Margret Brown, and I think it hasn't caught
on :)

RJF