[R] variable names when using S3 methods

[Aaron Rendahl]

I'm seeing some funny behavior when using methods (the older S3 type)  
and having variables that start with the same letter.  I have a vague  
recollection of reading something about this once but now can't seem  
to find anything in the documentation.  Any explanation, or a link to  
the proper documentation, if it does exist, would be appreciated.

Thanks, Aaron Rendahl
University of Minnesota School of Statistics


# set up two function that both use method "foo" but with different  
variable names
fooA<-function(model,...)
	UseMethod("foo")
fooB<-function(Bmodel,...)
	UseMethod("foo")

# now set up two methods (default and character) that have an  
additional variable
foo.character <- function(model, m=5,...)
	cat("foo.character: m is", m, "\n")
foo.default <- function(model, m=5,...)
	cat("foo.default: m is", m, "\n")

# both of these use foo.character, as expected
fooA("hi")
fooB("hi")

# but here, fooA uses foo.default instead
fooA("hi",m=1)
fooB("hi",m=1)

# additionally, these use foo.character, as expected
fooA("hi",1)
fooA(model="hi",m=1)