Re: [Groff] read-only number register

[SGT. Garcia]

On Mar 03  00:40 +0100, Ingo Schwarze wrote:
> A roff document can read from the number register (for example
> using the \n espace sequence) but cannot change the value of
> the register (for example, assigning to it with the .nr request
> won't work).
> 
> Yours,
>   Ingo

hello,
i guess i'm looking for a glossary. for example, what's a request? how is
it different from a macro?
and why would one want to read the number register. i came across
'register' reading about font families. i can make the connection between
what you're suggesting and what i have read here:
<https://www.gnu.org/software/groff/manual/html_node/Font-Families.html>

"The value at start-up is ‘T’. The current font family is available in the
read-only number register ‘.fam’ (this is a string-valued register); it is
associated with the current environment."