hi ted, philippe, and others---I agree with everything you write about good coding practice. none of us would be writing x<-3, even when we want to assign 3. we know better. we would at least use a space, if not a paren. alas, my suggestion is not so much for you. It is trying to spare novices that are just beginning to use R some unnecessary frustration. I bet that most of us have made this mistake at least once.
to the extent that it requires a token "<-[0-9]" to recognize this, it could be an easy special case/warning/error. to the extent that it requires more, it is probably not worth the hassle. [I am a great fan of syntax checking. I am not a great fan of many but the simplest recycling rules (from 1 to N) BY DEFAULT. It's just asking for trouble.] regards, /iaw ---- Ivo Welch (ivo.we...@brown.edu, ivo.we...@gmail.com) On Mon, Aug 23, 2010 at 4:27 PM, Philippe Grosjean <phgrosj...@sciviews.org> wrote: > I tell to my students that it is very important (not only for legibility) to > place spaces between operands. They have to write such a code like this: > > if (x < -3) do_something > > That way, there is no ambiguity. Don't you think it's important to write > clear code, including by using spaces where it makes it easier to read,... > and less ambiguous, as you just realize? > > Best, > > Philippe Grosjean > > On 23/08/10 19:06, Davor Cubranic wrote: >> >> On 2010-08-23, at 6:15 AM, Barry Rowlingson wrote: >> >>> On Sun, Aug 22, 2010 at 4:33 PM, ivo welch<ivo.we...@gmail.com> wrote: >>>> >>>> I have found that my students often make the mistake of >>>> mixing up comparisons and assignments with negative numbers: >>>> >>>> if (x<-3) do_something; >>> >>> If you tell your students not to use '<-' for assignment, then they >>> can't make this mistake, because = for assignment has additional >>> restrictions on it: >> >> The students are trying to *compare* to a negative number, and trip on R's >> parsing of "<-". They could use '=' for assignment all they want (which I >> thought is being discouraged as a code style these days, BTW), and they'll >> still run into this problem. >> >> Davor >> ______________________________________________ >> R-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel >> >> > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
