

x = foo(y:=bar(), baz(), y) or z
should work assuming foo bar and baz are functions being called?
if this is setting y to the effect of bar() + running baz after, then:
x = [bar(), baz()][0] or z
might work
and if you need y to be defined for later use:
x = [(y:=bar()), baz()][0] or z
but thats from memory, not sure if that will even run as written.
if I get to a real computer I'll try that with an actual if statement instead of a bastardized ternary.
Yeah, never said it was, just that if you really want to emulate that style you mostly can.