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Mark Hamburg <> wrote:
> Cute. I used to dislike this sort of thing, but it has a certain amount
> of resonance and leads to thoughts like the following:

I was thinking of languages like Smalltalk, C++, Java, etc, that allow you
to refer to instance variables without having to prefix with this or self.
Not sure if this is a good example to copy, though!

> Couple this with an import keyword that defines a local based on a
> require and you then are back to running global free most of the time.

A related idea is language support for strict globals, i.e. you can't use
a global without previously declaring it. All the languages I mentioned
above explicitly declare instance variables. When you use _ENV instead of
self, a global declaration becomes an instance variable declaration.

> But I can also see all sorts of ways this sort of cute approach to
> things makes things more fragile as well. For example, the above code
> ceases to do what you were expecting if you happen to define a local
> named slot1 or slot2.

One advantage of _ENV over setfenv() is that _ENV changes can be
discovered by simple syntactic analysis.

Still I think using _ENV for objects is probably too unidiomatic to be
worth using in real code.

f.anthony.n.finch  <>
Humber, Thames, Dover, Wight: Southeast, becoming variable, 3 or 4. Smooth or
slight. Fog patches then showers. Moderate, occasionally very poor.