Thank you Simon! Such a trivial explanation… admittedly, I am a bit disappointed, I hoped there was more to the mystery :)
Best, Taras > On 8 Mar 2021, at 03:51, Simon Urbanek <simon.urba...@r-project.org> wrote: > > 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
