R 2.12.2
Windows 7
Colleagues,
I just took advantage of the function:
readWindowsShortcut
in R.utils. It accomplished my goals and I was interested in learning its inner
workings. So, I typed the function at the command line (without arguments or
parentheses). R returned:
function (...)
UseMethod("readWindowsShortcut")
<environment: namespace:R.utils>
providing no insight to me as to the commands in the function.
So, how do I (or, can I) access the code in that function?
Thanks in advance
Dennis
Dennis Fisher MD
P < (The "P Less Than" Company)
Phone: 1-866-PLessThan (1-866-753-7784)
Fax: 1-866-PLessThan (1-866-753-7784)
www.PLessThan.com
Hi. On Mon, Mar 28, 2011 at 8:40 PM, Dennis Fisher <fisher at plessthan.com> wrote:> R 2.12.2 > Windows 7 > > Colleagues, > > I just took advantage of the function: > ? ? ? ?readWindowsShortcut > in R.utils. ?It accomplished my goals and I was interested in learning its inner workings. ?So, I typed the function at the command line (without arguments or parentheses). ?R returned: > > ? ? ? ?function (...) > ? ? ? ?UseMethod("readWindowsShortcut") > ? ? ? ?<environment: namespace:R.utils> > > providing no insight to me as to the commands in the function.That "UseMethod(...)" says that the method is a so called "S3 generic function", cf. help("UseMethod"). Simply speaking, when a generic function is called, it looks at the arguments sent to it and from those decides which "specialized method" of the same name should be called. To find out which "specialized methods" are available for a generic function, do:> methods("readWindowsShortcut")[1] readWindowsShortcut.default So, in this particular case, there is only one method. Also, whenever you see a method named <generic function>.default, it means that that method is the fallback method, which will be called if the generic function finds no better options. All what I said, is an extremely brief version of how (S3) method dispatch works.> > So, how do I (or, can I) access the code in that function?>From the above, the source code you are interested in can be found by:> print(readWindowsShortcut.default)/Henrik> > Thanks in advance > > Dennis > > > > Dennis Fisher MD > P < (The "P Less Than" Company) > Phone: 1-866-PLessThan (1-866-753-7784) > Fax: 1-866-PLessThan (1-866-753-7784) > www.PLessThan.com > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >
Dennis, I see that Henrik has given you a clear explanation of how to see the code 'on the fly'. But he's probably too modest to point out that it would be even better to inspect the source code which you can obtain by downloading and unzipping the relevant .tar.gz file from CRAN. Here you will find the code complete with useful comments. Peter Ehlers On 2011-03-28 20:40, Dennis Fisher wrote:> R 2.12.2 > Windows 7 > > Colleagues, > > I just took advantage of the function: > readWindowsShortcut > in R.utils. It accomplished my goals and I was interested in learning its inner workings. So, I typed the function at the command line (without arguments or parentheses). R returned: > > function (...) > UseMethod("readWindowsShortcut") > <environment: namespace:R.utils> > > providing no insight to me as to the commands in the function. > > So, how do I (or, can I) access the code in that function? > > Thanks in advance > > Dennis > > > > Dennis Fisher MD > P< (The "P Less Than" Company) > Phone: 1-866-PLessThan (1-866-753-7784) > Fax: 1-866-PLessThan (1-866-753-7784) > www.PLessThan.com > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.