From: Mathieu Bouchard <matju@...>
Date: 2001-02-26T03:27:33+09:00
Subject: [ruby-talk:11543] Re: RFC: RubyVM (long)

On Sun, 25 Feb 2001, Robert Feldt wrote:
> On Mon, 19 Feb 2001, Mathieu Bouchard wrote:
> > Could you send me that?
> It's been a busy week but I'll try to pack it up and send it in the coming
> days.

No problem, I took a week to reply to your previous large mail.

> Wel,, don't expect too much; I simply add the productions of one grammar
> to the ones of another. No checking that the merge is possible or that
> they "connect" (through a nonterminal or whatever). Do you know a
> "right"/better/more useful way to merge grammars?

No. I'm not too experienced with parsers. But this is not too urgent:
I'm not even sure we need a "Ruby--" parser at all. It could simply
be a subset of the syntax tree node types of the full Ruby and nothing
else.

textRuby ->  [parser]  -> nodeRuby
nodeRuby -> [compiler] -> nodeRuby--

since Ruby-- trees could be produced from Ruby trees, we don't need a
"textRuby--".

If for some reason we want to add a text version of "Ruby--" we then could
look into inheritable parser rulesets.

> Minor comment on ArrayMixin:
> (I haven't checked it thoroughly so maybe you already do this) Wouldn't it
> be better if put_many and get_many wasn't part of the Interface but was
> defined in ArrayMixin in terms of put/get. Then if people want better
> performance they can override these default version by defining their own
> and faster ones?

#get_many can be removed. I kept it there for performance concerns (one
call, many values). But then, #get can be removed instead. But I kept it
there for performance concerns (does not create an array). I didn't get
much feedback on this yet. There is another possible basic read operation 
I thought about last week:

#get_many2(anArray) -> nil takes a (real) Array as a parameter, in which
every element is a Fixnum in (0...length) (precondition). Replaces each
such element by its corresponding value in self.

(Basically, this is a slightly twisted form of #indices in which no array 
is created by the callee)

#put_many cannot be removed: it is the only way you can change the size of
the array. #put, on the other hand, can be removed.

This is an area in which I haven't decided anything yet though. What is
your opinion?

> > Well it's not a hindrance at all for me. I just use the & declarator to
> > pick up the special parameter, and then perform a .call on it where i
> > could do yield.
> You're right; that should be sufficient.

Except maybe for the arity issues (for which I don't remember all the
details) but at least an approximative solution is a good start. =)

> I'll post it. Aleksi mentioned maybe this should go into a cvs some
> place. Whats the eval criteria for being allowed to sit on the ruby
> cvs? How do you get "listed"?

just ask knu (Akinori Musha)



By the way... the grammar stuff in IRB seems to be incomplete. We'll have
to work from parse.y and/or the documentation's grammar file.



matju