[Rd] sys.call() inside replacement functions incorrectly returns *tmp*
@purdle@@ @ending from gm@il@com
Tue Oct 16 01:02:40 CEST 2018
> Although I'm not sure what problem it would solve...
Given that you asked, I was interested in writing a multiple assignment
function as a replacement function, so something like:
massign (x, y, z) = construct.some list ()
Obviously, that's not possible.
Probably the best example I can think of is converting cartesian
coordinates to polar coordinates.
Then we might have something like (note, untested, written in my email):
cart2polar = function (x, y)
list (theta=atan (y / x), r=sqrt (x * x + y * y) )
massign (r, theta) = cart2polar (x, y)
Now, I'm considering a multiple assignment operator, so something like:
c (theta, r) $<-$ cart2polar (x, y)
And while we're on the topic, I'm also considering an attribute operator
(to access object attributes), something like:
This would be similar to . in C++/Java or @ in S4.
And seems like something obvious that's missing from R.
Implementing an attribute read this way is easy, however, implementing an
attribute assignment this way (without language level support) is difficult.
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