Re: User-defined assignment

[noc.near.net!nic.umass.edu!hudson@uunet.uu.net (Rick Hudson)]

>>>>> On Sat, 17 Oct 1992 23:32:09 GMT, stt@spock.camb.inmet.com (Tucker Taft) 
said:

Tucker> Therefore, this sort of user-defined assignment is 
Tucker> supported, and Initialize and Finalize work correctly,
Tucker> in the presence of exceptions and abort.  (What this means
Tucker> is that Finalize is performed on an object if and only if Initialize
Tucker> is performed on the object, and both Initialize and Finalize defer abor
t
Tucker> until they complete, once they get started.)

It is probable wrong to formally specify that Finalize will *defer* abort
until it completes. Such a specification pretty much limits Ada to gc
strategies that utilize reference counts which are not as efficient
generational copying collectors. While such forms of memory management may be
the only strategies that are currently envisioned for Ada, similar languages
such as Modula-3 have shown that other solution are possible. If the Ada 9X
folks simply say that Finalization will eventually happen (possible
concurrently) then it doesn't cut off roads that might lead to interesting
places.
--

       Richard L. Hudson  -  Hudson@cs.umass.edu; (413) 545-1220; 
       Advanced Languages Project - University Computing Services
       Lederle Graduate Research Center
       University of Massachusetts             Amherst, MA  01003