[Groff] Line-drawing escape

[Miklos Somogyi]

Folks,

I used this macro for inserting dots between left- and right aligned 
test, a la   text1 .....  text2:

.de iD
\\$1  \\kx\\l'(\\n(.lu-\\nxu-\w'\\$2  'u).'  \\$2
..

It worked in troff, it works in groff.

I had an "insert space" version of this (replacing `.' with a space).
It worked in troff, but groff complains that `normal or special 
character expected (got a space)'.
\0 is a special character but no good either (got a node).

Is this a bug or a well-considered feature?
Is there a way to save this structure?

Well, I can always print text1 left-aligned and text2 right aligned, 
but still ...

Thank you,

Miklos