Macros for writing (German) letters?

[Tim Landscheidt]

Hi,

as background: I have been using Apache FOP
(https://xmlgraphics.apache.org/fop/) in the past to print
letters according to the German standard DIN 5008
(https://en.wikipedia.org/wiki/DIN_5008).  Since FOP is a
Java application and the support for Java in Fedora is
dwindling, I want to switch my workflow to groff.

I found Chris Schaller's macros
(https://lists.gnu.org/archive/html/groff/2010-09/msg00038.html)
which work, but feel not very integrated into the groff eco-
sphere.  I'd rather want to set up my new workflow on some
existing "framework" enhanced to accommodate the peculiari-
ties of the German standard.

It appears to me that the (only?) macro packages shipping
with groff which have "proper" support for writing letters
(i. e., macros that have a notion of sender, recipient,
date, etc.) are mom
(http://www.schaffter.ca/mom/momdoc/letters.html) and mm
(https://tkurtbond.github.io/troff/mm-all.pdf, appendix D).

Of the two, mm seems easier to extend as it is not only sig-
nificantly smaller :-), but also already has a structure for
different types of letters (BL, SB, FB, SP).

Am I missing some obvious alternative to produce letters ac-
cording to DIN 5008?

TIA,
Tim