Quoting Peng Yu <pengyu...@gmail.com>:
I feel tedious when I define a S4 class and the methods. For each
method, I have to call both setMethod and setGeneric (or both
setReplaceMethod and setGeneric). I would like a more compact grammar
so that I can reduce the key strokes. I'm wondering if there is a
better way available.
setClass(
Class='A',
representation=representation(
x='numeric'
)
)
setMethod(
f='initialize',
signature='A',
definition=function(.Object,x){
cat("~~~ A: initializator ~~~\n")
.Object<-callNextMethod(.Object,x=x)
return(.Object)
}
)
setGeneric('getx', function(object){
standardGeneric('getx')
}
)
setMethod('getx', 'A',
function(object){
return(obj...@x)
}
)
in some sense getx is redundant; x(obj) can only extract a value; more
so with setx(obj) <- value and x(obj) <- value (illustrating partly
that 'x' is a poor name for a slot).
setGeneric('setx<-', function(.object,value){
standardGeneric('setx<-')
}
)
setReplaceMethod(f='setx', signature='A',
def=function(.object,value){
.obj...@x<-value
return(.object)
}
)
one can create ad hoc getter / setter writers (e.g., in the
Bioconductor GSEABase package), but in the long run I have found these
to require more thought than the saved keystrokes are worth. You might
be more clever / disciplined than I. It's tempting to write getters /
setters as simple functions (setGeneric / setMethod is required
because the defined 'generic' isn't really that generic, it's just an
idiosyncratic accessor) but in the long run this also doesn't seem to
work well.
Martin
a=new(Class='A',x=10)
print(getx(a))
setx(a)<-5
print(getx(a))
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