Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> What's the best way for me to find out if a given parameter of a
> function is a constant? The context is that it's expensive to process,
> and in most cases will in fact be a constant, so if it is in fact a
> constant I'd like to process it once and stash the results.
I think we added get_fn_expr_arg_stable() for precisely that
purpose.
regards, tom lane