[squeak-dev] Re: immutibility

Colin Putney cputney at wiresong.ca
Thu Mar 18 14:51:28 UTC 2010


On 2010-03-18, at 5:39 AM, Bert Freudenberg wrote:

> HO there should be no way to reset the immutable flag. You can implement "soft" immutability in the image, but "hard" VM-level immutability needs to be permanent, no fiddling possible. Once set, the object stays immutable. Only a copy of an immutable object will be mutable again.

This would be good for some use cases - literals, for example, but not so good for others. One of the common uses of "immutability" is not so much to *prevent* mutation, as to control it: databases, concurrency etc. Do you have another feature in mind for these cases, or some overriding interest in immutable immutability that you want to pursue?

Colin


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