Thank You very much. This is a great help.
I would never ever have thought of either unRematchDefinition or getSrcref.
I will incorporate this new insight and report about any further
discoveries (or problems leading to them ;-))
Thanks again
Markus
2014/1/8 Duncan Murdoch <murdoch.dun...@gmail.com>
> On 14-01-07 2:40 PM, Markus Müller wrote:
>
>> For documentation we use a system that generates Rd files from special
>> comments in the code. (inlinedocs).
>> It is crucial to be able to get the defining source code for objects like
>> methods to extract the comments from it.
>>
>> Here is an R session that shows how this works for several kinds of
>> methods
>> and (at the end of the session) how if fails for methods of "initialize"
>>
>> require("methods")
>>> setGeneric( "myGen",function(arg){standardGeneric("myGen")})
>>>
>> [1] "myGen"
>>
>>> setMethod(
>>>
>> + f="myGen",
>> + signature="numeric",
>> + definition=function # a function with comments in its source
>> + ### that are used to document it with inlinedocs
>> + (arg ##<< another special comment for the argument
>> + ){
>> + 2*arg
>> + ### a description for the return value
>> + }
>> + )
>> [1] "myGen"
>>
>> we can get the whole function definition with comments back
>> by the following snippet:
>>
>>> attr(getMethod("myGen","numeric"),"srcref")
>>>
>> function # a function with comments in its source
>> ### that are used to document it with inlinedocs
>> (arg ##<< another special comment for the argument
>> ){
>> 2*arg
>> ### a description for the return value
>> }
>>
>>>
>>>
>> this also works for operators
>>
>> setMethod("$",
>>>
>> + signature(x = "MyClass"),
>> + function
>> + (x, ##<< first arg
>> + name ##<< second ag
>> + ) { }
>> + )
>> [1] "$"
>>
>>> attr(getMethod("$","MyClass"),"srcref")
>>>
>> function
>> (x, ##<< first arg
>> name ##<< second ag
>> ) { }
>>
>>>
>>> setClass(
>>>
>> + Class="MyClass",
>> + representation(
>> + val="numeric"
>> + )
>> + )
>>
>> It works also for other functions already defined:
>>
>> setGeneric("plot")
>>>
>> [1] "plot"
>>
>>> setMethod("plot",
>>>
>> + signature(x = "MyClass"),
>> + function # a comment
>> + (x, y, ...)
>> + {
>> + stop("need a definition for the method here")
>> + }
>> + )
>> [1] "plot"
>>
>>> attr(getMethod("plot","MyClass"),"srcref")
>>>
>> function # a comment
>> (x, y, ...)
>> {
>> stop("need a definition for the method here")
>> }
>>
>>>
>>>
>> However if we overload initialize there is no "srcref" attribute:
>>
>> setMethod(
>>>
>> + f="initialize",
>> + signature="MyClass",
>> + definition=function # here are also comments but we can not retrieve
>> them
>> + (.Object,value){
>> + .Object@val<- value
>> + return(.Object)
>> + }
>> + )
>> [1] "initialize"
>>
>>>
>>> attr(getMethod("initialize","MyClass"),"srcref")
>>>
>> NULL
>>
>> Is there a reason for this behavior, and more important still,
>> Ist there a way to get at the source of my constructors to document them
>> automatically?
>>
>
> I don't know the why of the design, but the comments are there, just not
> where you were looking. You can get them as follows:
>
> f <- getMethod("initialize", "MyClass")
> getSrcref(unRematchDefinition(f))
>
> This should work for the other cases too, where unRematchDefinition does
> nothing. I don't know if there are any cases where it will fail, but if
> there are, please let me know.
>
> Probably the getSrcref function should do this automatically when it sees
> that f is a method definition, but I'll wait to hear if it's the wrong
> approach.
>
> Duncan Murdoch
>
>
>
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