[R] Internal data types

[John D. Barnett]

Hi-

I'm very interested in using R, though I am still new to it.  However,
all of the data I'm working with is currently stored in Oracle.  So,
either I get data from Oracle, save it to a text file, and then import
it to R, or I write an R <-> Oracle bridge.  I've taken the second
approach, but I'm sure that I haven't done it entirely correctly.

For starters, is there any unified documentation for the R/C interface?

I can currently get back the results of a SQL query in a list of
vectors; however, the process is quite slow and CPU intensive.  This is
probably because I fill in the data structure in R, and call C to get
every single value.  It makes more sense to me to loop in C and create
the entire data structure there, but I'm not quite sure how to approach
this.

I think that what I want to do is actually create the appropriate SEXPR
for a list, with each element being a vector (numeric or string).  This
would presumably be through allocList() and allocVector(), but how then
do I access individual elements of an SEXPR (list or vector) from C?
(i.e., are there access functions that I'm missing, or do I have to wade
through the structure definition of SEXPR?)

Also, if I create the whole object in C, should I use dup=TRUE or FALSE
in the .C call?

Am I on the right track?

Thanks to anyone with more experience who can point me in the right
direction.

-John

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