Re: [Rd] Multiple return values / bug in rpart?
On Aug 13, 2013, at 5:27 AM, Barry Rowlingson wrote:
On Mon, Aug 12, 2013 at 6:06 PM, Justin Talbot justintal...@gmail.com wrote:
In the recommended package rpart (version 4.1-1), the file rpartpl.R
contains the following line:
return(x = x[!erase], y = y[!erase])
AFAIK, returning multiple values like this is not valid R. Is that
correct? I can't seem to make it work in my own code.
Works for me, returning a list:
foo
function(x){return(x,x*2)}
foo(99)
[[1]]
[1] 99
[[2]]
[1] 198
But hey, that might just be because I redefined 'return' earlier:
return
function(...){list(...)}
eek.. this is bad:
(function() { if(TRUE) return(OK); BAD! })()
[1] BAD!
Trying to modify the behavior of return() is rather tricky since you have to
return from the function that's calling you ...
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Re: [Rd] Multiple return values / bug in rpart?
I don't remember what rpartpl once did myself; as you point out it is a routine that is no longer used and should be removed. I've cc'd Brian since he maintains the rpart code. Long ago return() with multiple arguments was a legal shorthand for returning a list. This feature was depricated in Splus, I think even before R rose to prominence. I vaguely remember a time when it's usage generated a warning. The fact that I've never noticed this unused routine is somewhat embarrassing. Perhaps I need a not documented, never called addition to R CMD check to help me along. Terry Therneau In the recommended package rpart (version 4.1-1), the file rpartpl.R contains the following line: return(x = x[!erase], y = y[!erase]) AFAIK, returning multiple values like this is not valid R. Is that correct? I can't seem to make it work in my own code. It doesn't appear that rpartpl.R is used anywhere, so this may have never caused an issue. But it's tripping up my R compiler. Thanks, Justin Talbot __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Multiple return values / bug in rpart?
On 13/08/2013 13:54, Terry Therneau wrote: I don't remember what rpartpl once did myself; as you point out it is a routine that is no longer used and should be removed. I've cc'd Brian since he maintains the rpart code. Long ago return() with multiple arguments was a legal shorthand for returning a list. This feature was depricated in Splus, I think even before R rose to prominence. I vaguely remember a time when it's usage generated a warning. Yes, usage generated a warning then an error, but not parsing. foo - function() return(a=1, b=2) foo() Error in return(a = 1, b = 2) : multi-argument returns are not permitted The fact that I've never noticed this unused routine is somewhat embarrassing. Perhaps I need a not documented, never called addition to R CMD check to help me along. But you cannot know 'never called'. This is callable by rpart:::rpartpl() : it is also possible that functions in your namespace are called via eval()ing expressions at R or C level. (There are examples around for which that is the only usage.) Terry Therneau In the recommended package rpart (version 4.1-1), the file rpartpl.R contains the following line: return(x = x[!erase], y = y[!erase]) AFAIK, returning multiple values like this is not valid R. Is that correct? I can't seem to make it work in my own code. It doesn't appear that rpartpl.R is used anywhere, so this may have never caused an issue. But it's tripping up my R compiler. Thanks, Justin Talbot -- Brian D. Ripley, rip...@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UKFax: +44 1865 272595 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Multiple return values / bug in rpart?
On 13-08-13 8:59 AM, Prof Brian Ripley wrote: On 13/08/2013 13:54, Terry Therneau wrote: I don't remember what rpartpl once did myself; as you point out it is a routine that is no longer used and should be removed. I've cc'd Brian since he maintains the rpart code. Long ago return() with multiple arguments was a legal shorthand for returning a list. This feature was depricated in Splus, I think even before R rose to prominence. I vaguely remember a time when it's usage generated a warning. Yes, usage generated a warning then an error, but not parsing. foo - function() return(a=1, b=2) foo() Error in return(a = 1, b = 2) : multi-argument returns are not permitted The fact that I've never noticed this unused routine is somewhat embarrassing. Perhaps I need a not documented, never called addition to R CMD check to help me along. But you cannot know 'never called'. This is callable by rpart:::rpartpl() : it is also possible that functions in your namespace are called via eval()ing expressions at R or C level. (There are examples around for which that is the only usage.) An approximation to never called is to run Rprof on your test code, and see which functions are not mentioned. I have a package under construction with some students that can use this approach to identify which lines are never seen while profiling the test code. Duncan Murdoch __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Multiple return values / bug in rpart?
Both codetools and the compiler should be checking for use of multiple args in return -- I'll look into adding that. Best, luke On Tue, 13 Aug 2013, Duncan Murdoch wrote: On 13-08-13 8:59 AM, Prof Brian Ripley wrote: On 13/08/2013 13:54, Terry Therneau wrote: I don't remember what rpartpl once did myself; as you point out it is a routine that is no longer used and should be removed. I've cc'd Brian since he maintains the rpart code. Long ago return() with multiple arguments was a legal shorthand for returning a list. This feature was depricated in Splus, I think even before R rose to prominence. I vaguely remember a time when it's usage generated a warning. Yes, usage generated a warning then an error, but not parsing. foo - function() return(a=1, b=2) foo() Error in return(a = 1, b = 2) : multi-argument returns are not permitted The fact that I've never noticed this unused routine is somewhat embarrassing. Perhaps I need a not documented, never called addition to R CMD check to help me along. But you cannot know 'never called'. This is callable by rpart:::rpartpl() : it is also possible that functions in your namespace are called via eval()ing expressions at R or C level. (There are examples around for which that is the only usage.) An approximation to never called is to run Rprof on your test code, and see which functions are not mentioned. I have a package under construction with some students that can use this approach to identify which lines are never seen while profiling the test code. Duncan Murdoch __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Luke Tierney Chair, Statistics and Actuarial Science Ralph E. Wareham Professor of Mathematical Sciences University of Iowa Phone: 319-335-3386 Department of Statistics andFax: 319-335-3017 Actuarial Science 241 Schaeffer Hall email: luke-tier...@uiowa.edu Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] Multiple return values / bug in rpart?
And just in case anyone is curious about the history, return() with multiple arguments was legal in S2 but the syntax in the blue book had only return(expr), whether enforced or not in the code. John On 8/13/13 11:42 AM, luke-tier...@uiowa.edu wrote: Both codetools and the compiler should be checking for use of multiple args in return -- I'll look into adding that. Best, luke On Tue, 13 Aug 2013, Duncan Murdoch wrote: On 13-08-13 8:59 AM, Prof Brian Ripley wrote: On 13/08/2013 13:54, Terry Therneau wrote: I don't remember what rpartpl once did myself; as you point out it is a routine that is no longer used and should be removed. I've cc'd Brian since he maintains the rpart code. Long ago return() with multiple arguments was a legal shorthand for returning a list. This feature was depricated in Splus, I think even before R rose to prominence. I vaguely remember a time when it's usage generated a warning. Yes, usage generated a warning then an error, but not parsing. foo - function() return(a=1, b=2) foo() Error in return(a = 1, b = 2) : multi-argument returns are not permitted The fact that I've never noticed this unused routine is somewhat embarrassing. Perhaps I need a not documented, never called addition to R CMD check to help me along. But you cannot know 'never called'. This is callable by rpart:::rpartpl() : it is also possible that functions in your namespace are called via eval()ing expressions at R or C level. (There are examples around for which that is the only usage.) An approximation to never called is to run Rprof on your test code, and see which functions are not mentioned. I have a package under construction with some students that can use this approach to identify which lines are never seen while profiling the test code. Duncan Murdoch __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
[Rd] Multiple return values / bug in rpart?
In the recommended package rpart (version 4.1-1), the file rpartpl.R contains the following line: return(x = x[!erase], y = y[!erase]) AFAIK, returning multiple values like this is not valid R. Is that correct? I can't seem to make it work in my own code. It doesn't appear that rpartpl.R is used anywhere, so this may have never caused an issue. But it's tripping up my R compiler. Thanks, Justin Talbot __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
