Corey Huinker <corey.huinker@gmail.com> writes: > I was giving some thought to how psql handles undefined variables. > I would like an option where either psql can provide an alternate value > when an undefined variable is referenced, or a way to detect that a > specific variable is undefined and replace it with a defined variable.
This seems pretty bizarre. What's the use case? Why would it not be better to build the behavior out of other spare parts, along the lines of COALESCE or perhaps
\if not defined(x) \set x y \fi
Obviously the \if stuff is things we don't have yet either, but it seems less likely to have surprising side-effects.
Some form of DEFINED has more sense than COALESCE in this case. We can introduce some predefined client side functions available only in \if \elsif statements.