On 2017-05-07 3:46 PM, Duncan Murdoch wrote:
On 07/05/2017 3:56 PM, Spencer Graves wrote:
In an implied call to an S3 print method, deparse(substitute(x)) returns
"x", regardless of the name of object in .GlobalEnv, as indicated in the
following:
> Xnamed <- 1
> class(Xnamed) <- 'name.x'
> print.name.x <- function(x, ...){
+ namex <- deparse(substitute(x))
+ cat('How can I get the name of x in .GlobalEnv?\n',
+ 'deparse(substitute(x)) gives only ', namex, '\n')
+ }
> Xnamed
How can I get the name of x in .GlobalEnv?
deparse(substitute(x)) gives only x
My real application is print.findFn{sos}, which displays in a web
browser. If the results of multiple searches are "printed", the name of
the object in .GlobalEnv could help the user keep track of what was
done.
I don't think there's any way around this. Auto-printing of Xnamed
isn't equivalent to print(Xnamed); it doesn't happen until after
Xnamed is evaluated. It assigns the result to a local variable called
x, and calls print(x). (All of this is done in C code, and at that
point I don't think the original expression "Xnamed" is available any
more.)
For your application, you may have to allow users to attach names to
the object. I don't know how you're creating those things, but part
of the work could save a name as an attribute "SOSname", and then the
print method would use that.
Thanks for the reply. I'm already saving match.call() and
displaying that. That's adequate, but I was hoping to do better.
Spencer Graves
Duncan Murdoch
Thanks,
Spencer Graves
> sessionInfo()
R version 3.4.0 (2017-04-21)
Platform: x86_64-apple-darwin15.6.0 (64-bit)
Running under: macOS Sierra 10.12.4
Matrix products: default
BLAS:
/System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK:
/Library/Frameworks/R.framework/Versions/3.4/Resources/lib/libRlapack.dylib
locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] compiler_3.4.0 tools_3.4.0
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