[R-SIG-Mac] Example in body() help page, unexpected warning

David Winsemius dwinsemius at comcast.net
Sat Dec 26 22:45:03 CET 2009


I am getting a warning when using the example s on the help page for  
body:

 > f <- function(x) x^5
 > body(f) <- quote(5^x)
 > ## or equivalently  body(f) <- expression(5^x)
 > f(3) # = 125
[1] 125
 > body(f)
5^x
 >
 > ## creating a multi-expression body
 > e <- expression(y <- x^2, return(y)) # or a list
 > body(f) <- as.call(c(as.name("\{"), e))
Warning messages:
1: '\{' is an unrecognized escape in a character string
2: unrecognized escape removed from "\{"
 > f
function (x)
{
     y <- x^2
     return(y)
}
 > f(8)
[1] 64

The text of the Details section says that:
"The bodies of all but the simplest are braced expressions, that is  
calls to {: see the ‘Examples’ section for how to create such a call."

So I am puzzled that "\{" is being removed.
 > sessionInfo()
R version 2.10.1 RC (2009-12-09 r50695)
x86_64-apple-darwin9.8.0

locale:
[1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] grid      splines   stats     graphics  grDevices utils      
datasets  methods   base

other attached packages:
  [1] gplots_2.7.4    caTools_1.10    bitops_1.0-4.1  gdata_2.6.1      
gtools_2.6.1
  [6] hexbin_1.20.0   seqinr_2.0-7    kernlab_0.9-9   IDPmisc_1.1.06   
lattice_0.17-26
[11] Design_2.3-0    Hmisc_3.7-0     survival_2.35-7

loaded via a namespace (and not attached):
[1] cluster_1.12.1 tools_2.10.1

-- 

David Winsemius, MD
Heritage Laboratories
West Hartford, CT



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