Re: Nested R-expressions in r..eal

Wouter said:
"
Btw, for those who have used the older R
interface<http://www.swi-prolog.org/pldoc/package/R.html>in the past,
I have found r..eal to be a significant improvement over that
one (link to paper on
r..eal<http://bioinformatics.nki.nl/~nicos/pbs/padl2013-real.pdf
"
I agree that it is much better. However, I still use the older version because it is thread-safe.
If you use SWIPL in a web-served configuration, one needs to be careful in which server thread that R is called in.
With the new version, R is a dynamic library and so is not re-entrant safe against being called by different threads.
The old version used spawned R instances so although slower and more resource hungry this was guaranteed thread-safe as each thread had its own instance of R to communicate with.

I have a simple example of using Nicos's original R..eal interface in a web server configuration here:
http://entroplet.com/context_demos/navigate
Click on the "Use R .." link

This is slower than having R as a dynamic link ready for service requests.

This doesn't address the question of nested calls but we do support the idea of using R in Prolog apps, as R is the right tool for certain numerical and graphing applications.