Hi Paul, You might want to post this to the teaching list (R-sig-teaching). I'd look at packages written by old-timers and R Core. I've also found that most Bioconductor packages follow the guidelines you mention and many other excellent habits very well. I agree with you that these are very important things to teach.
Seb On Tue, 15 Feb 2011 12:04:42 -0600, Paul Johnson <pauljoh...@gmail.com> wrote: > Hello, I am looking for CRAN packages that don't teach bad habits. > Can I have suggestions? > I don't mean the recommended packages that come with R, I mean the > contributed ones. I've been sampling a lot of examples and am > surprised that many ignore seemingly agreed-upon principles of R > coding. In r-devel, almost everyone seems to support the "functional > programming" theme in Chambers's book on Software For Data Analysis, > but when I go look at randomly selected packages, programmers don't > follow that advice. > In particular: > 1. Functions must avoid "mystery variables from nowhere." > Consider a function's code, it should not be necessary to say "what's > variable X?" and go hunting in the commands that lead up to the > function call. If X is used in the function, it should be in a named > argument, or extracted from one of the named arguments. People who > rely on variables floating around in the user's environment are > creating hard-to-find bugs. > 2. We don't want functions with indirect effects (no <<- ), almost > always. > 3. Code should be vectorized where possible, C style for loops over > vector members should be avoided. > 4. We don't want gratuitous use of "return" at the end of functions. > Why do people still do that? > 5. Neatness counts. Code should look nice! Check out how beautiful > the functions in MASS look! I want code with spaces and " <- " rather > than everything jammed together with "=". > I don't mean to criticize any particular person's code in raising this > point. For teaching exemples, where to focus? > Here's one candidate I've found: > MNP. as far as I can tell, it meets the first 4 requirements. And it > has some very clear C code with it as well. I'm only hesitant there > because I'm not entirely sure that a package's C code should introduce > its own functions for handling vectors and matrices, when some general > purpose library might be more desirable. But that's a small point, > and clarity and completeness counts a great deal in my opinion. -- Seb ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
