[R-pkg-devel] RData files with identical objects in package

[peter dalgaard]

I think it is illegal if you use the lazyload database, because that is indexed by name and contains every object that would be created by data(). This creates an obvious issue if two objects share a name. 

Once you use the lazyload database, loading the package creates an environment which is initially full of promises, one for each object. Evaluating one of these makes the actual object appear in the environment. 

Using data() causes the corresponding promise(s) to be created in the global environment. IIRC, there is a registry that says which objects are created by which arguments to data(), but as they are still taken from the lazydata database, the last one created with a given name still wins.

-ps 

> On 13 Jan 2019, at 14:13 , Troels Ring <tring using gvdnet.dk> wrote:
> 
> Thanks a lot - I'm sure you are right that I could just use different names but I cannot understand why it could cause problem to have two different well formated .RData files in the /data directory both with an "x" - is that really illegal? I cannot see it stated in the official munual - but it is long (wrting r extensions)
> -BW
> Troels
> 
> -----Oprindelig meddelelse-----
> Fra: Michael Dewey <lists using dewey.myzen.co.uk> 
> Sendt: 13. januar 2019 12:56
> Til: Troels Ring <tring using gvdnet.dk>; package-develop <r-package-devel using r-project.org>
> Emne: Re: [R-pkg-devel] RData files with identical objects in package
> 
> Dear Troels
> 
> Perhaps I misunderstand what you are trying to do but would it be possible to put each x and y into a list or a dataframe with different names and then modify your usgae to pull them from there? Then there would be no danger of users getting the wrong x and y
> 
> Michael
> 
> On 13/01/2019 08:38, Troels Ring wrote:
>> Dear friends - I have a package under creation making heavy 
>> calculations on chemical/clinical data and I plan to include as 
>> "examples" the use of some literature data used in my papers. To 
>> illustrate what then occurs, I made two RData files consisting only of 
>> x and y with different values for x and y like
>> 
>> X <- 100
>> 
>> Y <- 1000
>> 
>> save(x,y,file="first.RData")
>> 
>> and then a new x and y in "second" with x <- 45 and y <- 32
>> 
>> When I put these in a "data" directory of a new package without 
>> further ado in RStudio
>> 
>> Ctrl-shift-L
>> 
>> Ctrl-shift-B
>> 
>> 
>> 
>> .there is a warning
>> 
>> * installing *source* package 'try' ...
>> 
>> ** R
>> 
>> ** data
>> 
>> *** moving datasets to lazyload DB
>> 
>> warning: objects 'x', 'y' are created by more than one data call
>> 
>> ** byte-compile and prepare package for lazy loading
>> 
>> ** help
>> 
>>   converting help for package 'try'
>> 
>> *** installing help indices
>> 
>>     finding HTML links ...    hello                                   html
>> 
>>  done
>> 
>> 
>> 
>> Now, when I clear the workspace:
>> 
>>> ls()
>> character(0)
>>> devtools::load_all(".")
>> Loading try
>> 
>> Restarting R session...
>> 
>>> library(try)
>>> ls()
>> character(0)
>>> x   #-- so even if workspace Is empty x is still kept
>> [1] 45
>>> data(first) # and "first" is not seen x
>> [1] 45
>> 
>> 
>> 
>> x is still present - and y
>> 
>> 
>> 
>> I have been reading and searching in "Writing R extensions" but so far
>> didn't find the clue.
>> 
>> Seemingly it is the file with the last name that is assessed - when I rename
>> first.RData to "xfile.RData" we get 100 and 1000.
>> 
>> Now and then when running ctrl-shift-L and - B we see
>> 
>> 
>> 
>> Attaches package: 'try'
>> 
>> The following objects are masked _by_ '.GlobalEnv':
>> x, y
>> 
>> 
>> 
>> Sorry for these problems -
>> 
>> BW
>> Troels
>> 
>> 
>> 	[[alternative HTML version deleted]]
>> 
>> ______________________________________________
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>> 
> 
> -- 
> Michael
> http://www.dewey.myzen.co.uk/home.html
> 
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-- 
Peter Dalgaard, Professor,
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