Running the S Evaluator from C
This discussion supplements that of Appendix A, with a few more
details and a couple of useful macros that may not be defined in your
current S/S-Plus. You should read this if you plan to use the S
evaluator from another application or to develop your own
front-end, say from a GUI.
For background, look at section 4.9 of the book to understand how the
S evaluator works, in addition to getting the basic ideas of C
programming from Appendix A.
There are two different situations we have in mind here:
The basic technique, fortunately, is the same in either case: to
construct an S expression object in C that represents the computation
to be done, and then to invoke the
- from an S session, we have gone into another environment,
perhaps a C subroutine, perhaps another language entirely, and
during this computation, we want to call back to S;
- we are taking over full control of the evaluation, as from a GUI or from a
verson of S embedded in some other process (we'll discuss embedding S separately).
EVAL macro in C to do
the evaluation and return the result.
Last modified: Mon Apr 26 17:21:39 Local time zone must be set--see zic manual page 1999