compile/?
Symbol: compile/? (surface: ?)
Syntax: (? COND THEN ELSE), (? COND THEN) with an else arm of
False, or (? COND), a boolean test only.
Behaviour: The two- and three-argument forms expand to
cond with an else: arm. The unary
form expands to (truth COND).
Examples:
>>> (? 1 "y" "n")
"y"
>>> (? 0 "y")
False
>>> (? "x")
True