On Fri, Jul 18, 2014 at 4:00 PM, Dario Strbenac
<dstr7320 at uni.sydney.edu.au> wrote:> Hello,
>
> capture.output produces a different result if the S4 object was created
with a constructor than if the body of the constructor is copied and pasted.
>
> setClass("TransformParams", representation(
> transform = "function",
> otherParams = "list")
> )
>
> setGeneric("TransformParams", function(transform, ...)
> {standardGeneric("TransformParams")})
> setMethod("TransformParams", character(0), function()
> {
> new("TransformParams", transform = function(){}, otherParams =
list())
> })
>
>> capture.output(TransformParams()@transform)
> [1] "function () " "{"
> [3] "}" "<environment:
0x363bd60>"
>> capture.output(new("TransformParams", transform =
function(){}, otherParams = list())@transform)
> [1] "function(){}"
>
> Why is the function split into three parts if a constructor is used ?
>
> --------------------------------------
> Dario Strbenac
> PhD Student
> University of Sydney
> Camperdown NSW 2050
> Australia
Dario,
When you use the constructor, the environment of the function is the
environment inside the constructor; when you use new() it is
R_GlobalEnv
The way functions print is that they print their environment when it
isn't something special like R_GlobalEnv. Since capture.output
captures the printed output, that's what it sees.
The function isn't split up; the printed output is.
-thomas
--
Thomas Lumley
Professor of Biostatistics
University of Auckland