A modest proposal (continued)

[Stuart D. Gathman]

In article <7xu1vvo432.fsf at ruckus.brouhaha.com>, "Paul Rubin"
<phr-n2001d at nightsong.com> wrote:

> I think it's more important to optimize locals and class attribute
> references (local.x.y.z), than globals.

The SymbolTable/array separation optimizes class attributes.  You missed
that section in my first post, so I'll repeat it in different words here.

The SymbolTable is stored with the class - initialized to all class
attributes mentioned in the code defined within the class.  The attribute
array is stored with each instance.  Dynamically adding attributes to a
class is handled by

a) growing the class SYmbolTable and expanding instance attribute arrays
as needed.  This could result in lots of unused instance slots when lots
of random identifiers are added dynamically.

b) keeping an auxilliary dictionary for attributes not mentioned in the
initial class definition.

I guess the big problem is accounting for a class possibly overriding
attribute fetching.  However, if we simply *always* call __getattr__, and
the default definition simply follows the same strategy as the load global
and is coded inline, then a class attribute lookup is essentially
equivalent to two optimized globals.

E.g.

    load class idxOf__getattr__		# cached like global access if not
    defined:
      load class idxOfName			   # cached like global access
    else:
      call __getattr__

-- 
	      Stuart D. Gathman <stuart at bmsi.com>
Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flamis acribus addictis" - background song for
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