[R] odd feature

[ivo welch]

Hi Thomas:

> One case where the vector-vector recycling rules are used is in
> vector-matrix operations:
>     a<-1:4
>     b<-diag(4)
>     a+b

is this last expression intended to be intuitive and thus desirable?
if anything else, I would end up writing something like this more as
an error than by intent.  I would suggest that recycling might be
better to be explicitly asked for by the user---though I am not sure
what the syntax should be.
       allow.recycle(a+b)
at the end, I think implicit recycling is a tradeoff between
convenience and unintended errors.  I would judge the convenience of
implicit recycling to be fairly low, and the unintended error rate
[with difficulty finding it] to be fairly high.

I guess the R language has few options() that control its
behavior---e.g., ala "use strict;" in perl.  If it did, I would love
to turn off implicit recycling, provided there is an explicit recycle
possibility.  I would not mind having the ability to be forced to
define variables first, either, though this is not a big deal.  R is
pretty good in telling me when I use variables that have not been
defined.

regards,

/ivo


>
>
>         -thomas
>