[R] How to comment in R

Stavros Macrakis macrakis at alum.mit.edu
Wed Feb 11 19:21:41 CET 2009


On Wed, Feb 11, 2009 at 12:32 PM, Greg Snow <Greg.Snow at imail.org> wrote:
> ...The c-style of /* */ allows both types and you can comment out part of a line, but it is not simple to match and has its own restrictions.  Friedl in his regular expressions book takes 10 pages to develop a pattern to match these (and the final pattern is almost 2 full lines of text in the book).  And this is without allowing nesting....

Though there is a real debate about the value of multiline, possibly
nested, comments, the regular expression argument is a red herring.
Lexical analysis of multiline comments is a solved problem (and not a
particularly difficult one!), and matters only to language and editor
implementors.  Emacs handles them with no problem.

           -s

PS And to give credit where credit is due (important on this mailing
list), the /* */ syntax was defined by PL/I; C simply implemented an
existing convention and popularized it. :-)



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