From: Brian Candler <B.Candler@...>
Date: 2003-02-01T21:59:21+09:00
Subject: Re: Local variables & blocks

> (guess no one read my other message on this)

I did. I'm just not really qualified to comment. But I will anyway :-) 

It always seemed strange to me that 'local variables' were not really part
of an object, and therefore seemed to break the OO model. I think what you
are proposing is to turn them into a special sort of instance variable: so

    x = 1

is a bit like

    @x = 1

except that the second case persists with the object for its entire
lifetime, whereas the first case persists only until the end of, erm, I'm
not quite sure - the current lexical scope? Perhaps then a new lexical scope
create a temporary subclass where these instance variables are deposited?
All method calls (including instances of local variables) will then follow
the normal chain of calling back up to the parent.

I'm not sure how this differs from the current situation though, if you
replace "temporary subclass" with "stack frame".

I suppose it might make local variables more widely available - for example:

class Foo
  def bar
    puts i
  end
  def baz
    i = 10
    bar
  end
end

Foo.new.baz  # doesn't work now

would allow the value of 'i' to be seen in 'bar' when called from 'baz'. If
that were desirable though, I'd have thought the current implementation
could allow it (e.g. by searching through all the stack frames, not just the
current one)

Regards,

Brian.