[R] turning R expressions into functions?

[Bert Gunter]

... or better still, the idiom used in update.default:

match.call(expand.dots=FALSE)$...

?
-- Bert

On Mon, Jul 23, 2012 at 2:45 PM, Bert Gunter <bgunter at gene.com> wrote:
> Bill:
>
> Is there some reason to prefer your "odd idiom" to match.call, perhaps
> as as.list(match.call()), as proposed by Hadley?
>
> -- Bert
>
> On Mon, Jul 23, 2012 at 2:25 PM, William Dunlap <wdunlap at tibco.com> wrote:
>> list(...) evaluates the things in ...
>> E.g.,
>>    > f0 <- function(x, ...) list(...)
>>    > f0(1, warning("Hmm"), stop("Oops"), cat("some output\n"))[[2]]
>>    Error in f0(1, warning("Hmm"), stop("Oops"), cat("some output\n")) : Oops
>>    In addition: Warning message:
>>    In f0(1, warning("Hmm"), stop("Oops"), cat("some output\n")) : Hmm
>>
>> You can use the odd idiom substitute(...()) to get the unevaluated ... arguments:
>>    > f1 <- function(x, ...) substitute(...())
>>    > f1(1, warning("Hmm"), stop("Oops"), cat("some output\n"))
>>    [[1]]
>>    warning("Hmm")
>>
>>    [[2]]
>>    stop("Oops")
>>
>>    [[3]]
>>    cat("some output\n")
>>
>>
>> Bill Dunlap
>> Spotfire, TIBCO Software
>> wdunlap tibco.com
>>
>>
>>> -----Original Message-----
>>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
>>> Behalf Of S Ellison
>>> Sent: Monday, July 23, 2012 2:12 PM
>>> To: Jochen Voß
>>> Cc: r-help at r-project.org
>>> Subject: Re: [R] turning R expressions into functions?
>>>
>>> >> One of the things I would love to add to my package would be the
>>> >> ability to compare more than two expressions in one call.  But
>>> >> unfortunately, I haven't found out so far whether (and if so, how) it
>>> >> is possible to extract the elements of a "..." object without
>>> >> evaluating them.
>>> >
>>> >Have a look at match.call.
>>>
>>> ... or use
>>> dotlist <- list(...)
>>>
>>> to get a list of everything included in ...
>>>
>>> S Ellison
>>>
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>>
>> ______________________________________________
>> R-help at r-project.org mailing list
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>> and provide commented, minimal, self-contained, reproducible code.
>
>
>
> --
>
> Bert Gunter
> Genentech Nonclinical Biostatistics
>
> Internal Contact Info:
> Phone: 467-7374
> Website:
> http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm