A primitive OO in R -- where next?

(Ted Harding) wrote:

Greetings All,

Out of curiosity, I've just done a very primitive experiment:

  Obj <- list(Fun=sum, Dat=c(1,2,3,4))
  Obj$Fun(Obj$Dat)
  # [1] 10

That sort of thing (much more sophisticated) must be documented
mind-blowingly somewhere. Where?

Where I stand right now: The above (and its immediately obvious
generalisations, like Obj$Fun<-cos) is all I know about it so far.

Well functions are just an object in R, so lists can of course contain 
them.  My naive understanding is that you can think of function calls
as 
simply lists where the first element is the function name, and the rest
of the list are the arguments, so:

 > eval(as.call(Obj))

[1] 10

Well, that's a neat trick! (It seems to depend on my having put the
function name first in the list, though, which wasn't done with any
specific intent).

In fact, the sort of thing I have in mind as possible applications
for the idea in that simple example, is that one could encapsulate
a "Study" in a list, which would contain as components the various
datasets available (quite possibly of different structures etc.),
and the various functions which one might use to analyse different
datasets, or to combine analyses, etc.; and possibly also a top-level
"supervisor" function which could ensure "social behaviour" in that
mob of entities. Pretty open-ended, really.

Ted.

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Date: 12-May-10                                       Time: 23:46:34
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