Re: About Constructions rules

[Chris Maden <crism@xxxxxxxxxxx>]

[Avi Kivity]
> On Thursday, July 15, 1999 23:31, Chris Maden [SMTP:crism@xxxxxxxxxxx]
> wrote:
> > But of course, you have to check every node against your list of
> > queries.  With only element construction rules, a very small
> > percentage of all nodes (usually) are candidates for a given
> > construction rule.  Evaluating every node will hose your
> > performance.  You can compile queries, of course, but with
> > arbitrary possible expressions, you'll always have potential
> > ratholes.

[10179 production [165] snipped]

> This means that the rule is called, at most, once per grove per
> mode. If any thrashing about is to be done, you have to specify it
> explicitly. And of course it can be done lazily.

IF you have the entire grove available.  But with people using SGML in
the real world on gigabyte documents, they don't want to do that.

And even so, when I started using (node-list-filter) expressions that
forced Jade to abandon its ignorance of individual character nodes,
processing time went up sixty fold (yes, that's 60, nearly two orders
of magnitude).  Pre-analysis of a query might allow the equivalent of
(select-by-class) to be done before the query is evaluated, but not
always.

-Chris
-- 
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