[developers] processing of lexical rules

[Bernd Kiefer]

Hi all,

i just want to describe shortly the solution i implemented in
negotiation with Berthold without being able to go into the linguistic
details about what is needed for the orthographemic component. Berthold
will send a mail about his point of view soon, but maybe not today or
tomorrow. 

We decided to re-install the application of the rule filter in the
morphological component of PET. This give the grammar writer the
possibility to exploit the restrictions about the successive
application of inflectional rules in the unification part already
during morphological analysis. Using the filter, which is optional, of
course breaks (in general) the intermediate application of lexical
rules (without spell changes), and might also provide a pitfall for an
unsuspicious grammar writer.

Berthold told me that he would be willing to sacrifice this (and have
all lexical rules in one block before or after the spell change rules)
if he would get the restrictions during morphological analysis. One of
his main objections against an external morpology component is, that
this makes it necessary to maintain to different lexical knowledge
sources, whereas he would like to describe the whole thing in one
grammar. 

One obvious problem with this approach is that constraints come from
two different sources: the lexicon entry of the base form and the rules
for spelling changes. It is of course prohibitively expensive to expand
all possible inflectional (and maybe interspersed lexical) rules
top-down to arrive at a point where either no base entry exists or it
is not compatible with the constructed feature structure.


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Bernd Kiefer                                            Am Blauberg 16
kiefer at dfki.de                                      66119 Saarbruecken
+49-681/302-5301 (office)                      +49-681/3904507  (home)
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