[Groff] on \$0

[Bernd Warken]

\\$0 refers to the macro name under which it a macro was called.
Unfortunately, \$0 is not set, that's a pity.  It would be great
for defining variable names that are local to a macro.  For example:

.de range:some_macro
.  ds \\$0:s
..
.als M range:some_macro


The local variable name `\\$0:s' expands to `M:s', but it should be
`range:some_macro:s'.


I would wish to be able to do:

.de range:some_macro
.  ds \$0:s            \" `\$0' is actually always empty.
..
.als M range:some_macro


Unfortunately, \$0 is not set at copy-in time.