"just-in-time" sub-grammar extraction

[Stephen Nightingale]

>I am looking for relevant work, and ideas, regarding the following
>practical problem in HPSG parsing:

>Given a large HPSG grammar and a short piece of text (a sentence, a
>passage, or even a document), efficiently extract a small HPSG sub-grammar
>(out of the larger one) that gives the same parsing and partial parsing
>(chart edges) results.  This would improve the parsing speed.


I was looking at this problem with respect to parsing it with an
ordinary (i.e procedural) chart parser, written in C++.  My
conclusion is that you have to tag the text in a prepass, and call
a subgrammar which accepts the surrounding tags.

In the HPSG context, the tags could be processed in the context of
a constraint:  the constraint effectively gives you the subgrammar.
With a declarative framework like HPSG (thinking in terms of ALE as
an implementation medium) I don't see that it is possible to fillet
out portions of the grammar.

Stephen.