Re: [Gretl-devel] scalar function args and NAs
On Sun, 5 Jul 2015, Sven Schreiber wrote:
Am 05.07.2015 um 17:08 schrieb Allin Cottrell:
>
> But maybe this is something we want to think about. Are there real
> use-cases where a function writer would want to accept NA for a bool or
> int argument? Or would it be more convenient for the writer not to have
> to bother with checking for NAs, in the knowledge that they would be
> ruled out by gretl?
>
Well, NaN rather than NA, but since they're not differentiated in gretl:
In principle I could imagine that a function has the log-value of something
as its input. Then the caller could write:
thefunc(log(thisvalue))
which could end up as thefunc(NA) for thisvalue <= 0. The question then is
really who should bear the burden of sanity checking, the function or the
caller.
Thanks, Sven. The log example would seem to pertain to parameters
marked as plain "scalar" rather than int or bool. My point was that
for int and bool parameters there's potentially a third option:
gretl itself could bear the burden of sanity checking -- unless,
that is, there's a real case for user-functions that are OK with
getting NAs for ints or bools. (Presumably such functions would
check for NA and treat it as meaning "not applicable".)
Allin