This works in v10:
a person has a relation of a person to a number called the friendship level.
To set the friendship of (p1 - a person) to (p2 - a person) to (n - a number):
now the friendship level of p1 relates p2 to n;
To decide what number is the friendship of (p1 - a person) to (p2 - a person):
if p2 relates to a number by the friendship level of p1, decide on the number to which p2 relates by the friendship level of p1;
decide on 0.
This changes some things.
It compiles in 6M62 but along with the other code in my example above (with the friendship-map bits removed) blows up on a runtime error in all of git, glulxe, quixe.