On Dec 7, 2010, at 12:42 PM, Gabor Grothendieck wrote:
On Tue, Dec 7, 2010 at 12:25 PM, Bert Gunter
<gunter.ber...@gene.com> wrote:
Ted:
Inline below...
On Tue, Dec 7, 2010 at 8:42 AM, Ted Harding
<ted.hard...@wlandres.net> wrote:
Indeed!
x <- x + 1
(and being generous with unnecessary spaces) uses 10 characters.
`+`(x)<-1
(being mean with them) uses 9. The "mean" version of the first
uses only 6: x<-x+1
However, I suppose there is merit in the spiritual exercise
of contemplating how `+`(x)<-1 gets worked out!
AFAICS it doesn't.
`+`(x)<-1
Error in +x <- 1 : could not find function "+<-"
Sorry, my code was missing the first line:
`+<-` <- `+`
x <- 3
`+`(x) <- 1
x
[1] 4
One can also attempt further creative violence to the language that
shows that is possible to construct unary operators like the C
prefix-"+" that do not require shift-9 <operand> shift-0.
> `+`
function (e1, e2) .Primitive("+")
> `+` <- `-` # in a different universe perhaps
> 4 + 2
[1] 2
> `+` <- function (e1, e2) .Primitive("+") # attempt to restore
> 4 + 2 # test
function (e1, e2) .Primitive("+") ## oops
> `+` <- .Primitive("+")
> 4 + 2
[1] 6 # "works"
> `!` <- function(x) x + 1 # hijacking a logical NOT definition
> !3
[1] 4 # so this is a redefinition of one of the two unary operators
# ( of which I am aware, I'm not an R-guru.)
> `!` <- .Primitive("!") ## hoping to restore expected behavior
> !3
[1] FALSE # whew. That seemed dangerous but I appear to have survived.
--
David Winsemius, MD
West Hartford, CT
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