ROBUSTNESS: x || y and x && y to give warning/error if length(x) != 1 or length(y) != 1

On Thu, Aug 30, 2018 at 5:58 PM Martin Maechler <maechler at stat.math.ethz.ch>
wrote:

I agree "in theory".
Thank you, Henrik, for bringing it up!

In practice I think we should start having a warning signalled.

I agree. I wouldn't know who would count on the automatic selection of the
first value, but better safe than sorry.

I have checked the source code in the mean time, and the check
is really very cheap
{ because it can/should be done after checking isNumber(): so
  then we know we have an atomic and can use XLENGTH() }

That was my idea as well after going through the source code. I didn't want
to state it as I don't know enough of the code base and couldn't see if
there were complications I missed. Thank you for confirming!

Cheers
Joris

Joris Meys
Statistical consultant

Department of Data Analysis and Mathematical Modelling
Ghent University
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