Off topic, but since I've observe both styles, does anyone know the history behind/reason for using ## instead of a single # to start comments in R. I know some editors do this by default. Is it because in C it is easier to distinguish (search/replace/...) comments from C preprocessor directives such as #include, and that's became a de facto standard elsewhere? /Henrik PS. I don't want to get into a debate on what's the best style.
OT: Reason/history behind ## notation for comments?
3 messages · Henrik Bengtsson, Laurent Gatto, Martin Maechler
For what concerns emacs users, the number of '#' has different effects on the position of the comment. From the ESS manual: 'By default, comments beginning with ?###? are aligned to the beginning of the line. Comments beginning with ?##? are aligned to the current level of indentation for the block containing the comment. Finally, comments beginning with ?#? are aligned to a column on the right...'. I guess that ## is the most wanted indentation for comments. Best wishes, Laurent
On 22 September 2010 07:26, Henrik Bengtsson <hb at stat.berkeley.edu> wrote:
Off topic, but since I've observe both styles, does anyone know the history behind/reason for using ## instead of a single # to start comments in R. ?I know some editors do this by default. ?Is it because in C it is easier to distinguish (search/replace/...) comments from C preprocessor directives such as #include, and that's became a de facto standard elsewhere? /Henrik PS. I don't want to get into a debate on what's the best style.
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1 day later
"LG" == Laurent Gatto <laurent.gatto at gmail.com>
on Wed, 22 Sep 2010 08:33:20 +0100 writes:
LG> For what concerns emacs users, the number of '#' has
LG> different effects on the position of the comment. From
LG> the ESS manual: 'By default, comments beginning with
LG> ?###? are aligned to the beginning of the line. Comments
LG> beginning with ?##? are aligned to the current level of
LG> indentation for the block containing the
LG> comment. Finally, comments beginning with ?#? are
LG> aligned to a column on the right...'. I guess that ## is
LG> the most wanted indentation for comments.
Yes, that's all correct.
(and Emacs+ESS being used quite a bit by some active R Core
members, at least "historically")
One thing to add:
As most of you probably know, R was built using ideas and
concepts from Lisp (aka "LISP"), and (Emacs-)Lisp being emacs'
extension language, Emacs has always supported
auto-indenting/filling of comments---which in lisp start with a
";" --- using different indentation rules for ";", ";;", ";;;" ....
So it seems quite apt for R to continue this Lisp convention.
Given the Lisp decent, this tradition is probably quite an old one in
(academic) programming history.
Martin Maechler,
ETH Zurich (and R Core)
LG> Best wishes,
LG> Laurent
LG> On 22 September 2010 07:26, Henrik Bengtsson
LG> <hb at stat.berkeley.edu> wrote:
>> Off topic, but since I've observe both styles, does
>> anyone know the history behind/reason for using ##
>> instead of a single # to start comments in R. ?I know
>> some editors do this by default. ?Is it because in C it
>> is easier to distinguish (search/replace/...) comments
>> from C preprocessor directives such as #include, and
>> that's became a de facto standard elsewhere?
>>
>> /Henrik
>>
>> PS. I don't want to get into a debate on what's the best
>> style.
>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
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LG> R-devel at r-project.org mailing list
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