[R] how to overwrite a Unary operator ?

[PO SU]

It's a good way to use RF OOS, but it's not my needing, actually, i want is there exists a way to write a  %++% form function that can pass one param to it?
So i can use  1%++%  to get 2 ,a<-2 , a%++% to get a<-3 .
It seems that the operator overwrite system in R, must pass two params. Is it true?




--

PO SU
mail: desolator88 at 163.com 
Majored in Statistics from SJTU



At 2014-10-18 00:54:40, "Greg Snow" <538280 at gmail.com> wrote:
>You may be interested in looking at Reference Classes/objects (see
>?setRefClass).  This is a form of OO programming that is more similar
>to C++ and Java.  You could create a counter object that you could
>then increment with syntax like:
>
>x$inc()
>x$inc(5)
>
>The first would increment by the default (1), the second would then
>increment by 5.
>
>
>
>On Fri, Oct 17, 2014 at 2:06 AM, PO SU <rhelpmaillist at 163.com> wrote:
>>
>> Tks for your alternative way's details. but like you mentioned in graphics package, i still wonder how to overload an operator which can pass one param like +2 .
>> There seems exists some examples for my needing. But i try to find them but without any results.
>> can you show me some examples from it?
>>
>>
>>
>>
>>
>>
>> --
>>
>> PO SU
>> mail: desolator88 at 163.com
>> Majored in Statistics from SJTU
>>
>>
>>
>> At 2014-10-17 15:16:47, "David Winsemius" <dwinsemius at comcast.net> wrote:
>>>
>>>On Oct 16, 2014, at 10:36 PM, PO SU wrote:
>>>
>>>>
>>>> Tks for your advice,  let the ++ problem alone, how to write an
>>>> Unary operator ? Is it permitted in R?
>>>> such    as    a<-2 , a%+2%  will let a  be 4 .
>>>
>>>OK, that's just wrong. Oh, OK, just for fun, as it were:
>>>
>>>inc <- function(x)
>>>{
>>>  eval.parent(substitute(x <- x + 1))
>>>}
>>>
>>>
>>> > inc(10)
>>>Error in 10 <- 10 + 1 : invalid (do_set) left-hand side to assignment
>>> > y=10
>>> > inc(y)
>>> > y
>>>[1] 11
>>>
>>>
>>>> I just want to know it , i won't pollute r with it , because i know
>>>> what is r .  : )
>>>>
>>>It's certainly permitted. Just look at all the overloadings of the "+"
>>>operator in graphics packages. Look up the documentation on methods in
>>>R.
>>>
>>>Why not just use a well-behaved function, though?
>>>
>>>.inc <- function(x) x+1
>>> > .inc(10)
>>>[1] 11
>>>
>>>Then you won't be tempted to try 10 <- .inc(10) because it just
>>>wouldn't make sense.
>>>
>>>--
>>>David.
>>>
>>>> --
>>>>
>>>> PO SU
>>>> mail: desolator88 at 163.com
>>>> Majored in Statistics from SJTU
>>>>
>>>>
>>>>
>>>>
>>>> At 2014-10-17 13:09:47, "Rolf Turner" <r.turner at auckland.ac.nz> wrote:
>>>>> On 17/10/14 17:29, PO SU wrote:
>>>>>>
>>>>>> Dear expeRts,
>>>>>>   Now i want to know how to implement an Unary operator like  i++
>>>>>> in cpp's  synax form.
>>>>>>   e.g.   2++  will let 2 be 3 ,  a<-2 ,a++ ,will let a be 3
>>>>>> I tried this :
>>>>>>  '%++%'<-function(x){
>>>>>>    x<<-x+1
>>>>>> }
>>>>>> but it have problem, the biggest one is it seems the function need
>>>>>> twoparams like a%++%b , how to write a function needing just one
>>>>>> param?
>>>>>>
>>>>>> TKS !
>>>>>
>>>>> Just ***DON'T***.  The "++" operator is useful only for those wish to
>>>>> write code which is obscure to the point of incomprehensibility.  It
>>>>> makes C and its offspring "write only" languages.
>>>>>
>>>>> If you are going to use R, use R and don't pollute it with such
>>>>> abominations.
>>>>>
>>>>> cheers,
>>>>>
>>>>> Rolf Turner
>>>>>
>>>>>
>>>>> --
>>>>> Rolf Turner
>>>>> Technical Editor ANZJS
>>>> ______________________________________________
>>>> R-help at r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>>David Winsemius, MD
>>>Alameda, CA, USA
>>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>
>
>-- 
>Gregory (Greg) L. Snow Ph.D.
>538280 at gmail.com