bash_completer_word_break_characters customization?

[Robert Anderson]

Recently I tried to figure out how to get bash to complete filenames
that use a leading '='.  The default behavior is to offer all the files
in the directory when completing a filename with a leading '=':

rwa@lan1(~/bash)$ touch a b =file
rwa@lan1(~/bash)$ more =
=file  a      b      

I found that I could get the behavior I wanted by modifying
bash_completer_word_break_characters to not include "=".  I suspect that
there are good reasons that "=" is in the word break group, and that
leading = filenames a rare enough special case not to warrant that
change as an absolute. (?)

However, it occured to me that a nice way to handle this would be to
allow the char set considered for word breaks to be customizable, say
through an environment variable, with the default being hardcoded as it
is.

Not being a shell expert, it wasn't immediately clear to me how to
accomplish this, although to a shell expert it may be.

Comments?

Thanks,
Bob