From: "Jörg W Mittag" <JoergWMittag+Usenet@...>
Date: 2009-08-10T21:10:24+09:00
Subject: Re: Kind of ParsTree for 1.9.1

Robert Dober wrote:
> On Sun, Aug 9, 2009 at 3:24 AM, Charles Oliver
> Nutter<headius@headius.com> wrote:
>> On Wed, Aug 5, 2009 at 9:56 AM, Brian Candler<b.candler@pobox.com> wrote:
>>
>> And again, that ignores that the AST is ever-changing and usually very
>> different across impls.
> I guess if I could really chose I would like a switch, and would like
> the VM to keep the AST iff that switch is set (-a|--ast).
> Goo{df} idea?

Unfortunately, by then it will already be too late. There's nothing
the VM can do about it. That's exactly the reason why ParseTree
doesn't work on YARV: the only component that needs the parsetree is
the compiler. By the time the compiler hands off the code to the VM,
the parsetree is long gone. The same applies to XRuby and Ruby.NET as
well as the AOT modes of Rubinius, JRuby, IronRuby and MacRuby.

And remember that the compiler and the VM need not be run by the same
person, on the same machine or at the same time. In HotRuby, for
example, the compiler is generally run by the web developer on the web
server at development time whereas the VM is run by the user inside
the browser on the client, maybe months after the code was compiled.

jwm