[Rd] Extract method for a new class

[Coster, Albart]

Dear list,

I am trying to write a package for simulating meioses in R. We defined a class 'haplotype' which contains the basic units of our simulation:

setClass("haplotype",representation(snp = "numeric",qtl = "list",
                                    hID = "numeric",phID0 = "numeric",phID1 = "numeric"),
                                    prototype = list(hID = 0,phID0 = NaN,phID1 = NaN))

In addition, we define a class 'haploList', which is just a list of haplotypes:

setClass("haploList",contains = "list",representation(genDist = "numeric",roundDec = "integer"))

Most things work fine, but when subsetting a haploList object an object of class list is returned. I realize that I need to write a function for subsetting this new object, and tried to find the code for '[.listof' or something similar could not find it, probably due to a suboptimal understanding of how it is organized. 

My question is, how could I define a extraction function for my new class that uses all the existing functionality of the Extract function for list? 

Thanks in advance,

Albart Coster