Hello,
I have questions while reviewing "chron" package(e.g.,chron.R).
1. What is the differences between 3 kinds of function definition ?
1) "name" <- function(...
2) 'name' <- function(...
3) name <- function(...
Do you know Why author used various kinds of definitions ?
Is there no functional differences between them ?
2. I don't understand the meaning of the below code:
as.chron <- function(x, ...) UseMethod("as.chron")
as.chron.default <- function (x, format, ...)
{ ....
Could you let me know what is role of UseMethod("as.chron") ?
3. In the following code,
"chron" <-
function(dates. = NULL, times. = NULL,
format = c(dates = "m/d/y", times = "h:m:s"),
out.format, origin.)
'dates', 'origin' and 'times' has dot(.) as at the end of word.
Do you know the meaning of dots ?
4. Could you introduce me some books on S/R language, especially for
understanding of generic functions ?
Some interesting packages such as quantmod, xts, zoo, etc., are seems to be
coded using generic functions(UseMethod(..)).
But I can't easily understand the code.
Thanks in advance,
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