[developers] case distinctions in (R)MRS predicates and constants

Stephan Oepen oe at csli.Stanford.EDU
Sat Mar 31 09:22:06 CEST 2007

hi again,

> > i would like to elicit a quick policy decision regarding (R)MRS names
> > (yes, something as easy as that :-).  i believe it is meant for PREDs
> > _and_ CARG values not to be case-sensitive.  the former, i expect, is
> > non-controversial.  for the latter, someone might think that "foo" and
> > "Foo" should be distinct constants (parameters).  personally, i see no
> > practical value in making that distinction, but i have no preferences
> > either way.  in a sense, less downcasing might be the right thing ...
> We discussed this during Deep Thought and decided that all PREDs are
> case insensitive (written as lower case) and that CARG values are case
> sensitive.  I believe that Dan, for one, argued that he wanted this
> distinction to be available.

i am about to check in a few changes to make the above true.  the older
LKB code always upcased CARGs when constructing the semantic index, and
when looking up entries.  however, when instantiating an entry, it used
to take the CARG verbatim, hence failing to instantiate whenever there
were case mismatches.  e.g. named_rel[ CARG "abrams" ] would no longer
generate with recent versions of the ERG, where dan has now introduced
capitalization distinctions ("Ana" vs. "ANA" could provide an example).

the problem with the above code asymmetry was that there is a facility
for uknown name (and numbers et al.) generation in the ERG, using a set
of generic lexical entries (to be documented :-).  however, the trigger
for that code is an empty return value from index look-up, and with the
obligatory upcasing, the failure would not be visible at that point ...

anyway, this change should be transparent to most people.  if anything 
it will improve generation results for those using the ERG.

                                                           best  -  oe

+++ Universitetet i Oslo (IFI); Boks 1080 Blindern; 0316 Oslo; (+47) 2284 0125
+++     CSLI Stanford; Ventura Hall; Stanford, CA 94305; (+1 650) 723 0515
+++       --- oe at csli.stanford.edu; oe at ifi.uio.no; oepen at idi.ntnu.no ---

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