Re: [Gretl-devel] another ternary woe
Am 26.01.2017 um 23:00 schrieb Allin Cottrell:
On Thu, 26 Jan 2017, Sven Schreiber wrote:
>
> <hansl>
> matrix heyho = ("a" == "b") ? garbl[3,] : I(2)
> </hansl>
>
> There is no object "garbl", but that's by design in the case that the
> condition isn't true. Gretl says "[" would be invalid here.
That's because '[' is accepted the by parser only if it's preceded by
the name of an object of a type that can be subsetted. We don't actually
evaluate the LHS of a ternary expression if the antecedent is false, but
we always have to parse it. There may be some way around this, but the
practical answer is: use "if" in this sort of case.
Just a quick follow-up: I stumbled over a similar issue again (in my
johansensmall.gfn package), and given your response the workaround is
clear. But I noticed that the error message (with 2017a) is that (the
equivalent of) the symbol "garbl" is undefined, whereas above/before I
had reported the error to be "[ invalid". Don't know if that has a
deeper meaning or if it's expected for you.
cheers,
sven