Language.R.GC

Facilities to get Haskell's garbage collector to manage the liveness of values allocated on the R heap. By default, R values remain live so long as the current region is extant. The R garbage collector may only free them after the end of the region. Sometimes, this discipline incurs too high of a memory usage and nested regions are not always a solution.

This module enables registering a callback with the GHC garbage collector. In this way, when the GHC garbage collector detects that a value is no longer live, we can notify the R garbage collector of this fact. The R garbage collector is then free to deallocate the memory associated with the value soon after that.

This module hence offers an alternative, more flexible memory management discipline, at a performance cost. In particular, collections of many small, short-lived objects are best managed using regions.

Documentation

automatic :: MonadR m => SEXP s a -> m (SEXP G a)

Declare memory management for this value to be automatic. That is, the memory associated with it may be freed as soon as the garbage collector notices that it is safe to do so.

Values with automatic memory management are tagged with the global region. The reason is that just like for other global values, deallocation of the value can never be observed. Indeed, it is a mere "optimization" to deallocate the value sooner - it would still be semantically correct to never deallocate it at all.

automaticSome :: MonadR m => SomeSEXP s -> m (SomeSEXP G)

automatic for SomeSEXP.