it's a value! it's a reference!, was Substitutability, was Re: Finding the spirit of L-World

Brian Goetz brian.goetz at
Sun Feb 24 03:12:31 UTC 2019

> The best I can do is "content*" vs. "identity*"

For what its worth: identity* classes are _aliasable_, whereas content* classes are not.  For a reference to an identity* instance, assignment: 

    r1 = r2 

creates an alias; for a reference to a content* instance

    r3 = r4

creates a copy.

But none of these words really attempt to describe what refs*/values* _are_; they describe how they _behave_.  Which seems a little limited for wanting adjectives that modify “object” or “reference” or “class”.   

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