[developers] Expanding a grammar with defaults

[Emily M. Bender]

I've been meaning to recast the lex rule types in the matrix
using `lexical' defaults, if by that we mean ones that are all
resolved a compile time.  I'm hoping I can use this to make
the preservation of information up chains of lexical rules easier.
The current solution is pretty clunky.

Emily


On Wed, Feb 25, 2009 at 8:38 PM, Ann Copestake
<Ann.Copestake at cl.cam.ac.uk> wrote:
>
> well, if there are no other cases of `/', it's safe!
>
> I don't think anyone would have a use for persistent defaults, other
> than admiring their beauty in the feature structures, unless they'd
> written their own code to convert the TDFSs into something.  They
> aren't handled by the MRS code and I'm fairly sure that the code that
> I used when playing with them never made it into a distributed LKB.
>
> Cheers,
>
> Ann
>
>>
>> G'day,
>>
>> I believe that approach should work, assuming all defaults are
>> > `lexical' rather than `persistent'.  I'd be happy to try and advise if
>> > there seem to be problems
>>
>>
>> Thank you.
>>
>> Ann
>>
>>
>> The value of *description-persistence* is L, and the only default I could
>> find was:
>>
>> lexeme := canon-sign &
>>  [ ORTH [ LIST [ REST #last ],
>>           LAST #last ],
>>    SYN [ HEAD.TOPIC /l -,
>>          LEX +,
>>          VAL.GAP <! !> ],
>>    SEM [ HOOK [ LTOP #ltop,
>>                 INDEX #index ],
>>          KEY #key & [ LBL #ltop,
>>                       ARG0 #index ],
>>          RELS.LIST.FIRST #key ] ].
>>
>> So it looks as though we are in luck :-).
>>
>> Is there any way of testing for the existence of persistent defaults?
>>
>> --
>> Francis Bond <http://www2.nict.go.jp/x/x161/en/member/bond/>
>> NICT Language Infrastructure Group
>>
>> --001636e1fcd92a039f0463cad2a1
>> Content-Type: text/html; charset=UTF-8
>> Content-Transfer-Encoding: quoted-printable
>>
>> G&#39;day,<br><br><div class=3D"gmail_quote"><blockquote class=3D"gmail_quo=
>> te" style=3D"border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt=
>>  0.8ex; padding-left: 1ex;">
>> I believe that approach should work, assuming all defaults are<br>
>> `lexical&#39; rather than `persistent&#39;. =C2=A0I&#39;d be happy to try a=
>> nd advise if<br>
>> there seem to be problems</blockquote><div>=C2=A0<br>Thank you.<br><br></di=
>> v><blockquote class=3D"gmail_quote" style=3D"border-left: 1px solid rgb(204=
>> , 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><font color=3D"=
>> #888888">
>> Ann</font></blockquote><div>=C2=A0</div><div>The value of *description-pers=
>> istence* is L, and the only default I could find was: <br><br>lexeme :=3D c=
>> anon-sign &amp;<br>=C2=A0[ ORTH [ LIST [ REST #last ], <br>=C2=A0=C2=A0=C2=
>> =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 LAST #last ],<br>
>> =C2=A0=C2=A0 SYN [ HEAD.TOPIC /l -,<br>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
>> =C2=A0=C2=A0 LEX +,<br>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 VAL=
>> .GAP &lt;! !&gt; ],<br>=C2=A0=C2=A0 SEM [ HOOK [ LTOP #ltop,<br>=C2=A0=C2=
>> =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
>> =C2=A0 INDEX #index ],<br>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 =
>> KEY #key &amp; [ LBL #ltop,<br>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
>> =A0=C2=A0 ARG0 #index ],<br>
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 RELS.LIST.FIRST #key ] ].<=
>> br><br>So it looks as though we are in luck :-).<br><br>Is there any way of=
>>  testing for the existence of persistent defaults?<br></div></div><br>-- <b=
>> r>Francis Bond &lt;<a href=3D"http://www2.nict.go.jp/x/x161/en/member/bond/=
>> ">http://www2.nict.go.jp/x/x161/en/member/bond/</a>&gt;<br>
>> NICT Language Infrastructure Group<br>
>>
>> --001636e1fcd92a039f0463cad2a1--
>
>