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info-dylan-digest V1 #24



    Date: Mon, 12 Jun 2000 11:15:01 -0400 (EDT)
    From: "Scott McKay" <swm@mediaone.net>

    Hugh Greene wrote in message ...
    >An alternative is to reserve a few "tag" bits in the first word [...]
[...]    
    But really, what with Java running on everything, in a sane world
    all new architectures would have a few tags that represent all the
    Java primitive types (or at least int, float, char, and "pointer").
    Then you alias the primitive types to their object classes (int and
    Integer, e.g.), and voila` -- you're back to Lisp and SmallTalk
    circa 1980, putting Java only 20 years behind instead of 30.  :-(

Strangely enough, or perhaps nowhere NEAR strangely enough, this was the
substance of a proposal from Olin Shivers to extend the JVM to accept
dynamically typed code.  I think there was also an "instruction pointer" which
meant that, instead of an instruction, some plugin native code would get called.
(Fahlman had previously proposed pretty much the same "writeable control store"
idea, with some fribbles to make it reasonably secure.)

Ah, here it is:

Shivers, Olin.  "Supporting dynamic languages on the Java virtual machine", MIT
 AI Memo 1576, April 1996, 9 pages.
 URL: ftp://publications.ai.mit.edu/ai-publications/1500-1999/AIM-1576.ps

No, Sun didn't buy it.  Pity.