[R] I don't understand this

[Thomas Lumley]

On Tue, 2 Sep 2003, Simon Fear wrote:

> Please choose answer:
> a) you beat me to it making a great point
> b) it's got two too many pairs of braces in it, that's whats wrong with
> it!
>
> But seriously, I am sure Richard O'K had no intention of doing any such
> thing.
> The question was just about the syntax of R, no?
>
> Isn't it the case that
>
> (expr)(expr)
>
> is incorrect syntax under any circumstances?

Nope.

It's *usually* incorrect, but not always

  power<-function(lambda) function(x) x^lambda

  (power(3))(2)

is perfectly valid.

You could also define, say, %*% to be a composition operator on some group
of functions and write
  (f %*% g)(x)
quite sensibly.


It may be the case that (expr)(expr)<-  is always invalid.


	-thomas