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Re: Boxes: halfway through the comment period and no comments
On 05/17/2013 11:09 AM, John Cowan wrote:
Can I assume that means everyone on this list is entirely happy with
them exactly as written? Ghu knows, boxes are simple, which is why
I picked them as the first R7RS-large effort. But a little feedback
wouldn't hurt either.
They're simple, but the interactions with other concepts aren't
My first question is: what is the relationship between boxes and
promises? Is a promise a kind of box? I.e. a promise is a box
that can only be set once? Are they both subtypes
of something else? Would you use a box to implement a promise?
The "auto-boxing" section clearly has parallels with similar optional
features of promises, so there a clear connections. It's surprising
they're not actually discussed.
See this discussion of "blank promises", which is even more of
a "set-once" box:
Also, what about more general types of boxes. For example
computed boxes, which are defined in terms of getter/setter functions.
Or being able to register a callback function ("listener"), which is
called when value the in box is changed. In some models you can
register arbitrary numbers of listeners.