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

[Prof Brian Ripley]

On Sun, 27 Dec 2009, David Winsemius wrote:

>
> On Dec 27, 2009, at 2:07 AM, Prof Brian Ripley wrote:
>
>> Hmm, when I run example(body) I get
>> 
>> body> body(f) <- as.call(c(as.name("{"), e))
>> 
>> with no backslash.  And text help and the refman also have no backslash.
>> 
>> So, how are you doing this?  Cut-and-paste from HTML help?
>
> Yes; that was how I entered it, but just now I entered this line from the 
> keyboard and got the same result:
>
>> body(f) <- as.call(c(as.name("\{"), e))
> Warning messages:
> 1: '\{' is an unrecognized escape in a character string
> 2: unrecognized escape removed from "\{"

Correct, as that is not a valid string in R ... R-devel gives an 
error.

>
>
> --
>> 
>> I suspect this is yet another rendering problem with HTML help: I've fixed 
>> quite a few since 2.10.1 was released.
>> 
>> On Sat, 26 Dec 2009, David Winsemius wrote:
>> 
>>> 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.
>> 
>> That is *not* what the message says: it says the backslash is being 
>> removed.
>> 
>>>> sessionInfo()
>>> R version 2.10.1 RC (2009-12-09 r50695)
>>> x86_64-apple-darwin9.8.0
>> 
>> Please update to a released version.
>> 
>>> 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
>>> 
>>> _______________________________________________
>>> R-SIG-Mac mailing list
>>> R-SIG-Mac at stat.math.ethz.ch
>>> https://stat.ethz.ch/mailman/listinfo/r-sig-mac
>> 
>> -- 
>> Brian D. Ripley,                  ripley at 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, UK                Fax:  +44 1865 272595
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>

-- 
Brian D. Ripley,                  ripley at 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, UK                Fax:  +44 1865 272595