From: Trans <transfire@...>
Date: 2005-04-16T03:14:37+09:00
Subject: Re: class locals as class methods

Actually I should go further with this...

The idea of a clean nomenclature is very appealing, which is one of the
resons the idea of this thread is appealing to me. But I do see the
point of the "scratch-pad" variable. What's interesting though, is that
it is this distinction that really matters: whether the var is
temporary or permanant. How do we mark that distinction now? Lo, it's
not as far from what I had imagined as it is, actually. You can define
just such a variable using an @ sign. Of course you still need to
create the accessor methods to go with it:

  class X
    @a = 1
    def self.a ; @a ; end
    def self.a=(x) ; @a = x ; end
  end

But this is what gets me when I think about it. It is this form --the
accessor form, that requires all this extra footwork; not the
"scratch-pad" local vars. You'd think it were the local vars that were
most commonly used then, but they aren't. So it would seem preferable
to make the locals the ones with the extra syntax, either in defining
them like a := 1 or a prefix, like %a = 1 or something.

Yet, going further, we might take this down to the method level too. It
has been suggested before (and I think quite reasonably) that we could
have local methods:

  class X
    def a
      def b
        "1"
      end
      b
    end
  end

In this case #b is local to #a. Applying the idea of this thread in
this context would mean that local vars are local methods too. So,

  class X
    def a
      b = "1"
      b
    end
  end

would be equivalent to the previous example. Here, again the
"scratch-pad" critique posses an issue. In effect the local vars are
becoming persistant. So, we could make a distinction between the
persitant vs. non-persistant to deal with this, but in this case the
syntax it is not quite as clear b/c local vars are much more common in
this method context.

T.