Re: [Rd] Sweave tokens not in column 1: enhancement request

From: David.Epstein <>
Date: Wed, 20 Apr 2011 07:17:25 -0700 (PDT)

Friedrich Leisch-2 wrote:

>>>>>> On Tue, 19 Apr 2011 13:59:44 -0700 (PDT),
>>>>>> David Epstein (DE) wrote:

> > When I re-use a code chunk in Sweave, together with keep.source=TRUE,
> I would
> > like to follow usual programming conventions in which the amount of
> white
> > space on the left indicates logical structure. It seems that one can't
> do
> > this in Sweave, or am I wrong?
> > for (i in ind) {
> > do such-and-such and then
> > <<code chunk 20>>
> > do something-else
> > }
> Not difficult at all, that's a trivial change:
> MySyntax <- utils::SweaveSyntaxNoweb
> MySyntax$coderef <- "^[[:space:]]*<<(.*)>>.*"
> Sweave("test.Rnw", syntax=MySyntax)
> should do what you want. That code references need to start in column 1
> is inherited from noweb, not sure if we really need it. Cannot think
> of a situation where the above regular expression appears in valid R
> code, but perhaps I am overlooking something.

Thanks. That is indeed very simple. I should have started this thread in R-help, as I know there are other users who would like to do this, but I mistakenly thought that code development would be needed. Is it possible to somehow transfer the thread to R-help?

Would it not be safer to use [:blank:] or [ \t] instead of [:space:]? [:space:] allows several symbols apart from space and tab, and this might cause trouble?

Is it possible to put something into the .Rnw file with the same effect, or do you HAVE to work from outside Sweave? Thanks

View this message in context:
Sent from the R devel mailing list archive at

______________________________________________ mailing list
Received on Thu 21 Apr 2011 - 06:59:41 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Thu 21 Apr 2011 - 07:00:50 GMT.

Mailing list information is available at Please read the posting guide before posting to the list.

list of date sections of archive