Taras, I don't think this has anything to do with promises, rather it is called Just-In-Time (JIT) compilation - see ?enablleJIT in R, it is enabled by default, so the function will be compiled on second use.
Cheers, Simon > On Mar 7, 2021, at 11:12 PM, Taras Zakharko <taras.zakha...@uzh.ch> wrote: > > Dear all, > > I was playing around with some C code that inspects argument promises and I > noticed that forwarded arguments sometimes contain bytecode in the PRCODE > component. E.g. if I have a nested call like this: > > f <- function(x) x > g <- function(x) f(x) > > g(1+1) > > and inspect the value of “x” in g’s frame from within f’s frame (basically > calling findVar(parent.frame(), x)), I would see a LANGSXP the first time g() > is invoked, but BCODESXP on every subsequent time. Using PREXPR gets me the > original LANGSXP in any case. > > Now, this is curious behavior and I had a quick glance into R source code > related to closure evaluation and argument matching, but I could not see > anything that would generate bytecode for promises. Could someone with > in-depth knowledge of R’s machinery explain what is going on? > > Thanks, > > Taras > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
