Example was complicated, but here is a simpler form
continueIfTrue <- function(mm=return()){
eval(mm)
}
telemStats <- function(){
y <- substitute(return())
continueIfTrue(y)
print("I would not like this message to be printed")
}
telemStats()
Ideally, calling telemStats() should return to the prompt and the
print in telemStats should not appear
On Mon, Mar 16, 2015 at 4:02 PM, David Winsemius <dwinsemius at
comcast.net> wrote:>
> On Mar 16, 2015, at 3:08 PM, Saptarshi Guha wrote:
>
>> Hello,
>>
>> I would like a function X to return to the place that called the
>> function XParent that called this function X.
>>
>> Y calls XParent
>> Y = function(){
>> XParent()
>> print("hello")
>> }
>>
>> XParent calls X
>>
>> XParent = function(){
>> X()
>> print("H")
>> }
>>
>> X returns to the point just after the call to XParent. Hence
>> print("H") is not called, but instead "hello" is
printed.
>
> ?sys.call # my second reading of your question makes me think this
wasn't what was requested.
>
> ?return # this would do what was asked for
>
>> XParent = function(){
> + return(sys.call())
> + print("H")
> + }
>> Y()
> [1] "hello"
>
> # Success
> # now to show that a value could be returned if desired
>
>> Y = function(){
> + print(XParent())
> + print("hello")
> + }
>> XParent = function(){
> + return(sys.call())
> + print("H")
> + }
>> Y()
> XParent()
> [1] "hello"
>
>
>>
>> X returns to the point just after the call to XParent. Hence
>> print("H") is not called, but instead "hello" is
printed.
>>
>> An example of what i'm going for is this
>>
>> continueIfTrue <- function(filterExp, grpname, subname,n=1){
>> y <- substitute(filterExp)
>> res <- isn(eval(y, envir=parent.frame()),FALSE)
>> ## if res is FALSE, I would like to return from telemStats
>> }
>>
>> telemStats <- function(a,b){
>> b <- c(10,12)
>> continueIfTrue( { length(b) >=10 },
"progStats","00")
>> print("Since the above condition failed, I would not like this
>> message to be printed")
>> }
>
> I'm afraid there were too many undefined objects to make much sense of
that example.
>
>>
>> I looked into callCC and signals but dont think i understood correctly.
>> Any hints would be appreciated
>>
>> Kind Regards
>> Saptarshi
>>
> --
>
> David Winsemius
> Alameda, CA, USA
>
On Mar 16, 2015, at 5:05 PM, Saptarshi Guha wrote:> Example was complicated, but here is a simpler form > > continueIfTrue <- function(mm=return()){ > eval(mm) > }What are you trying to accomplish by passing `return()` to a formal parameter?> telemStats <- function(){ > y <- substitute(return())That last bit of code doesn't make a lot of sense either. The `substitute` function is specifically designed to NOT evaluate the first argument but rather to return an unevaluated call. If you wanted to actually "return" from that function you would assuredly not use `return` within the substitute argument. You need to explain what you want to accomplish rather than posting failed code. -- David.> continueIfTrue(y) > print("I would not like this message to be printed") > } > telemStats() > > > Ideally, calling telemStats() should return to the prompt and the > print in telemStats should not appear > > > On Mon, Mar 16, 2015 at 4:02 PM, David Winsemius <dwinsemius at comcast.net> wrote: >> >> On Mar 16, 2015, at 3:08 PM, Saptarshi Guha wrote: >> >>> Hello, >>> >>> I would like a function X to return to the place that called the >>> function XParent that called this function X. >>> >>> Y calls XParent >>> Y = function(){ >>> XParent() >>> print("hello") >>> } >>> >>> XParent calls X >>> >>> XParent = function(){ >>> X() >>> print("H") >>> } >>> >>> X returns to the point just after the call to XParent. Hence >>> print("H") is not called, but instead "hello" is printed. >> >> ?sys.call # my second reading of your question makes me think this wasn't what was requested. >> >> ?return # this would do what was asked for >> >>> XParent = function(){ >> + return(sys.call()) >> + print("H") >> + } >>> Y() >> [1] "hello" >> >> # Success >> # now to show that a value could be returned if desired >> >>> Y = function(){ >> + print(XParent()) >> + print("hello") >> + } >>> XParent = function(){ >> + return(sys.call()) >> + print("H") >> + } >>> Y() >> XParent() >> [1] "hello" >> >> >>> >>> X returns to the point just after the call to XParent. Hence >>> print("H") is not called, but instead "hello" is printed. >>> >>> An example of what i'm going for is this >>> >>> continueIfTrue <- function(filterExp, grpname, subname,n=1){ >>> y <- substitute(filterExp) >>> res <- isn(eval(y, envir=parent.frame()),FALSE) >>> ## if res is FALSE, I would like to return from telemStats >>> } >>> >>> telemStats <- function(a,b){ >>> b <- c(10,12) >>> continueIfTrue( { length(b) >=10 }, "progStats","00") >>> print("Since the above condition failed, I would not like this >>> message to be printed") >>> } >> >> I'm afraid there were too many undefined objects to make much sense of that example. >> >>> >>> I looked into callCC and signals but dont think i understood correctly. >>> Any hints would be appreciated >>> >>> Kind Regards >>> Saptarshi >>> >> -- >> >> David Winsemius >> Alameda, CA, USA >>David Winsemius Alameda, CA, USA
On 3/17/2015 10:01 AM, David Winsemius wrote:> On Mar 16, 2015, at 5:05 PM, Saptarshi Guha wrote: > >> Example was complicated, but here is a simpler form >> >> continueIfTrue <- function(mm=return()){ >> eval(mm) >> } > What are you trying to accomplish by passing `return()` to a formal parameter?Might returning a logical serve your purpose? Then you could say "if(!continueIfTrue(...))return(...)". Will this do what you want? Spencer> >> telemStats <- function(){ >> y <- substitute(return()) > That last bit of code doesn't make a lot of sense either. The `substitute` function is specifically designed to NOT evaluate the first argument but rather to return an unevaluated call. If you wanted to actually "return" from that function you would assuredly not use `return` within the substitute argument. > > You need to explain what you want to accomplish rather than posting failed code. >
On 03/16/2015 05:05 PM, Saptarshi Guha wrote:> Example was complicated, but here is a simpler form > > continueIfTrue <- function(mm=return()){ > eval(mm) > } > telemStats <- function(){ > y <- substitute(return()) > continueIfTrue(y) > print("I would not like this message to be printed") > } > telemStats() > > > Ideally, calling telemStats() should return to the prompt and the > print in telemStats should not appearhere's one way to implement your original example -- signal and handle, via tryCatch(), a custom condition created (modelled after simpleCondition()) as an S3 class with linear inheritance. X <- function() { print("I'm saying...") signalCondition(structure(list(), class=c("my", "condition"))) print("X") } Y <- function(){ tryCatch(XParent(), my=function(...) NULL) print("hello") } XParent <- function(){ X() print("H") } leading to > Y() [1] "I'm saying..." [1] "hello" callCC() is tricky for me to grasp, but I'll write Y to accept an argument X, which will be a function. It'll call XParent with that function, and XParent will use the function. Y <- function(X){ XParent(X) print("hello") } XParent <- function(X){ X("fun") print("H") } then we've got > Y(X) Error in XParent(X) (from tmp.R!4361C1Y#2) : object 'X' not found > Y(function(x) print("X")) [1] "X" [1] "H" [1] "hello" but more interestingly the long jump to the top (where callCC was invoked) > callCC(function(X) { Y(X) }) [1] "fun" or in a function y <- function() { value <- callCC(function(X) { Y(X) }) print(value) print("done") } Hope that helps and is not too misleading. Excellent question. Martin> > > On Mon, Mar 16, 2015 at 4:02 PM, David Winsemius <dwinsemius at comcast.net> wrote: >> >> On Mar 16, 2015, at 3:08 PM, Saptarshi Guha wrote: >> >>> Hello, >>> >>> I would like a function X to return to the place that called the >>> function XParent that called this function X. >>> >>> Y calls XParent >>> Y = function(){ >>> XParent() >>> print("hello") >>> } >>> >>> XParent calls X >>> >>> XParent = function(){ >>> X() >>> print("H") >>> } >>> >>> X returns to the point just after the call to XParent. Hence >>> print("H") is not called, but instead "hello" is printed. >> >> ?sys.call # my second reading of your question makes me think this wasn't what was requested. >> >> ?return # this would do what was asked for >> >>> XParent = function(){ >> + return(sys.call()) >> + print("H") >> + } >>> Y() >> [1] "hello" >> >> # Success >> # now to show that a value could be returned if desired >> >>> Y = function(){ >> + print(XParent()) >> + print("hello") >> + } >>> XParent = function(){ >> + return(sys.call()) >> + print("H") >> + } >>> Y() >> XParent() >> [1] "hello" >> >> >>> >>> X returns to the point just after the call to XParent. Hence >>> print("H") is not called, but instead "hello" is printed. >>> >>> An example of what i'm going for is this >>> >>> continueIfTrue <- function(filterExp, grpname, subname,n=1){ >>> y <- substitute(filterExp) >>> res <- isn(eval(y, envir=parent.frame()),FALSE) >>> ## if res is FALSE, I would like to return from telemStats >>> } >>> >>> telemStats <- function(a,b){ >>> b <- c(10,12) >>> continueIfTrue( { length(b) >=10 }, "progStats","00") >>> print("Since the above condition failed, I would not like this >>> message to be printed") >>> } >> >> I'm afraid there were too many undefined objects to make much sense of that example. >> >>> >>> I looked into callCC and signals but dont think i understood correctly. >>> Any hints would be appreciated >>> >>> Kind Regards >>> Saptarshi >>> >> -- >> >> David Winsemius >> Alameda, CA, USA >> > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. >-- Computational Biology / Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N. PO Box 19024 Seattle, WA 98109 Location: Arnold Building M1 B861 Phone: (206) 667-2793