1. I am not aware of a difference, and don't know why the various forms were used.
2. That handles identifying the correct function to call based on the types of arguments supplied when the function was called. Read about the S4 object-oriented programming features to learn about method dispatch.
3. It has no syntactic effect. Using periods in parameter names may make it less likely to be the same as names defined by the user, but only if the user cooperates by avoiding that naming convention.
4. There is some quite good documentation supplied with R. You can also look on CRAN (http://www.r-project.org/doc/bib/R-publications.html).
Please read the posting guide, and post in plain text.
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"박상규" <birdfire94 at naver.com> wrote:
>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,
>
>
>
>
> [[alternative HTML version deleted]]
>
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