Another fun, exciting reason to use singular they for your variable names: the object and possessive forms are totally distinct (example sentence taken from the pronoun dressing room):
That smile of theirs really makes me happy. I could talk to them all day although they don’t talk about themself much. I wonder if their day has been wonderful. I hope so!
Compare:
That smile of hers really makes me happy. I could talk to her all day although she doesn’t talk about herself much. I wonder if her day has been wonderful. I hope so!
Or the masculine:
That smile of his really makes me happy. I could talk to him all day although he doesn’t talk about himself much. I wonder if his day has been wonderful. I hope so!
My pronoun initiation code block in my WIP looks like this:
Block of code ~10 lines
*create they "he"
*create their "his"
*create them "him"
*create theirs "his"
*create themself "himself"
*create theyre "he's"
*create are "is"
*create were "was"
*create theyve "he's"
*create have "has"
*create plural false
The boolean flag is what I use for multireplace for verb forms, when distinguishing between plural verbs for singular they and the more usual singular verbs.
Surely you want to know who ${h_they} @{h_plural meet|meets} with.