How do you transform an instance of the old type to the new type? On Thu, Feb 4, 2016 at 9:27 PM, Cedric St-Jean <cedric.stj...@gmail.com> wrote:
> One could do a deepcopy-like traversal of everything starting from the GC > roots and replace all instances of the old type with the new type... > Obviously a very costly operation, but it might be cool to offer that in a > package. > > On Thursday, February 4, 2016 at 6:34:00 PM UTC-5, Stefan Karpinski wrote: >> >> That would mean that redefining a type of which there are any (reachable) >> instances would invalidate the entire system. That seems significantly >> worse than simply not allowing types to be redefined without restarting. >> One could potentially make references to "invalidated" objects #undef, but >> that seems likely to leave the object graph in a completely unusable state. >> >> On Thu, Feb 4, 2016 at 6:11 PM, Michael Landis <darksky...@gmail.com> >> wrote: >> >>> They would be invalid too. I know... no garbage collector, so it would >>> be necessary to find the inbound references. Smart pointers maybe? Yet >>> another performance hit. >>> >>> On Thursday, February 4, 2016 at 1:54:24 PM UTC-8, Stefan Karpinski >>> wrote: >>>> >>>> How does one "release" an object? What happens to other objects that >>>> retain references to those objects? >>>> >>>> On Thu, Feb 4, 2016 at 4:35 PM, Michael Landis <darksky...@gmail.com> >>>> wrote: >>>> >>>>> if you added a field, the existing objects could still be valid. If >>>>> you killed an attribute, they are invalid and can be released. >>>>> >>>>> On Thursday, February 4, 2016 at 10:55:25 AM UTC-8, Stefan Karpinski >>>>> wrote: >>>>>> >>>>>> What happens to existing objects of a type when you redefine the type? >>>>>> >>>>>> On Thu, Feb 4, 2016 at 1:46 PM, Michael Landis <darksky...@gmail.com> >>>>>> wrote: >>>>>> >>>>>>> I think it would be nice to be able to undefine a type, so >>>>>>> restarting the environment is not required when adding or deleting an >>>>>>> attribute from a type description. Not being able to update a type >>>>>>> definition without restarting the environment is a royal pain in the >>>>>>> ass. >>>>>>> >>>>>>> >>>>>>> On Saturday, March 8, 2014 at 9:55:37 AM UTC-8, Freddy Chua wrote: >>>>>>>> >>>>>>>> Suppose I have a Type >>>>>>>> >>>>>>>> type Foo >>>>>>>> a >>>>>>>> b >>>>>>>> end >>>>>>>> >>>>>>>> f = Foo(1,2) >>>>>>>> f.a = 1 >>>>>>>> f.b = 2 >>>>>>>> >>>>>>>> how do I test whether f.a is defined >>>>>>>> I do this isdefined(f, 1) but isdefined(f, 'a') does not work >>>>>>>> >>>>>>>> another question >>>>>>>> how do i undefine f.a such that isdefined(f,1) now returns false >>>>>>>> >>>>>>> >>>>>> >>>> >>
