search for: maybe_referenc

> To allow for future changes in the way the need for duplication is > detected in R internal C code, package C code should avoid direct > use of NAMED,and SET_NAMED, or assumptions on the maximal value > of NAMED. Use the macros MAYBE_REFERENCED, MAYBE_SHARED, and > MARK_NOT_MUTABLE instead. These currently correspond to > > MAYBE_REFERENCED(x): NAMED(x) > 0 > MAYBE_SHARED(x): NAMED(x) > 1 > MARK_NOT_MUTABLE(x): SET_NAMED(c, NAMEDMAX) > > Best, > > luke Checking https://cran.r-project.org/d...

Hi all, I'm wondering if there is any way to define a `SET_ELT` function for an ALTREP class? I see there are ` ALTINTEGER_SET_ELT` etc. functions exported in Rinternal.h, but there is no corresponding ALTREP APIs to define them. The only way to set the value of an ALTREP is through a pointer, which will require that the ALTREP data is in memory. Is it on purpose? Will there be any plan to

...method for ALTSTRING classes but not yet for others. I seem to recall that there are some issues with going there for others, but we'll probably take a closer look later this year. One thing to keep in mind is that the R pass-by-value semantics require that C code duplicate an object for which MAYBE_REFERENCED is true, and the assumption in existing code is that duplicate returns an object that can safely be mutated. That places a lot of limitations on what can be done. You can see some notes on the issues in the README.md and the vignette in https://github.com/ALTREP-examples/Rpkg-mutable. Best, luk...

This wouldn't actually work at present as evaluating a promise always sets NAMED to 2. With reference counting it would work so might be worth considering when we switch. Going forward it would be best to use MAYBE_REFERENCED to test whether a duplicate is needed -- this macro is defined appropriately whether R is compiled to use NAMED or reference counting. Best, luke On Fri, 21 Aug 2015, William Dunlap wrote: > Does R have a function like the S/S++ unset() function? > unset(name) would remove 'name'...

Does R have a function like the S/S++ unset() function? unset(name) would remove 'name' from the current evaluation frame and return its value. It allowed you to safely avoid some memory copying when calling .C or .Call. E.g., suppose you had C code like #include <R.h> #include <Rinternals.h> SEXP add1(SEXP pX) { int nProtected = 0; int n = Rf_length(pX);

...ler for all supported C++ standards (e.g., -std=gnu++11 for the C++11 compiler). Previously this was not done in a few cases where the default standard passed the tests made (e.g. clang 6.0.0 for C++11). C-LEVEL FACILITIES: * 'Writing R Extensions' documents macros MAYBE_REFERENCED, MAYBE_SHARED and MARK_NOT_MUTABLE that should be used by package C code instead NAMED or SET_NAMED. * The object header layout has been changed to support merging the ALTREP branch. This requires re-installing packages that use compiled code. * 'Writing R Ex...

...ler for all supported C++ standards (e.g., -std=gnu++11 for the C++11 compiler). Previously this was not done in a few cases where the default standard passed the tests made (e.g. clang 6.0.0 for C++11). C-LEVEL FACILITIES: * 'Writing R Extensions' documents macros MAYBE_REFERENCED, MAYBE_SHARED and MARK_NOT_MUTABLE that should be used by package C code instead NAMED or SET_NAMED. * The object header layout has been changed to support merging the ALTREP branch. This requires re-installing packages that use compiled code. * 'Writing R Ex...