From: "Sean E. Russell" <ser@...>
Date: 2006-02-01T12:06:58+09:00
Subject: Re: Question about massive API changes

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On Tuesday 31 January 2006 14:44, mathew wrote:
> > What do you mean by an API facade?
>
> Something that accepts calls via the old API, and translates them into
> appropriate calls into the new API.

I thought that's what you meant.  Unfortunately, that's not the API I'm=20
talking about.

In REXML, currently, you can do this:

	el.attributes['someatt'] =3D "foo"
	el.attributes['someatt'] << "bar"
	el.attributes['someatt'] =3D=3D "foobar"    # true

I can do this, because the attributes are being stored as Attribute objects=
,=20
even though you get back String objects from attributes[].  To get the spac=
e=20
saving, I'm only generating Attribute objects when the user makes an API ca=
ll=20
that returns an Attribute object; otherwise, I store the original String=20
objects, which are less than 1/3 the size of an Attribute object.  Dependin=
g=20
on the XML document, this can save a significant amount of memory.  The sam=
e=20
trick will be applied to Text nodes, for even more savings.  On my average=
=20
document survey, for example, I get about a 50% space improvement.

See:

http://www.germane-software.com/repos/rexml/branches/memory_attributes/benc=
hmarks/memoryuse/stats.svg

for a *very* rough benchmark.  (trunk) is the current REXML memory use, (gn=
s)=20
is the optimized use, with just Attributes using optimized.

This isn't something I can put a fa=E7ade on -- at least, not without wreck=
ing=20
the memory gain.  As soon as I create a non-primitive object out of it, I=20
lose the gain.

> Having seen the response to suggestions of incorporating versioning and
> RubyGems into Ruby, I think I could hazard a guess...

I didn't see anybody objecting to the versioning aspect of RubyGems; just t=
he=20
package management aspect of it.  In fact, I clearly remember some vocal=20
insistence that the best thing would be to separate versioning from package=
=20
management, where it doesn't belong... but that discussion is pass=E9.

=2D-=20
=2D-- SER

"As democracy is perfected, the office of president represents,=20
more and more closely, the inner soul of the people.  On some=20
great and glorious day the plain folks of the land will reach=20
their heart's desire at last and the White House will be adorned=20
by a downright moron."        -  H.L. Mencken (1880 - 1956)

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