Semantic Caseframe Parsing & Syntactic Generality

We nave implemented a restricted .:lommn parser called Plume "M Building on previous work at Carneg=e-Mellon Unfvers=ty e.g. [4, 5. 81. Plume s approacn to oars=ng ~s based on semantic caseframe mstant~a~on Th~s nas the advantages of effic=ency on g r i n ~at ical ,nput. and robustness in the face of ungrammatmcal tnput Wh~le Plume ~s well adapted to s=mpte ,:;~ectaratwe and ~mperat=ve utterances, it handles 0ass=yes relatmve clauses anti =nterrogatives in an act noc manner leading to patciny syntact=c coverage Th~s paOe, oulhnes Plume as =t Currently exfsts and descr,Oes our detaded des=gn for extending Plume to handle passives rela|~ve clauses, and =nterrogatlves ~n a general manner 1 The Plume Parser Recent work at Carnegie-Mellon Umvers=ly eg . [4. 51 has sinown semanttc caseframe =nstant~ation to be a n,ghly robust and efficient method of parsing restricted domain ~n0ut. In tn~S approach ~0 parsing, a caseframe grammar contains lhe doma~n-soecific semantic informat=on, ana" the pars=ng program contains general syntact=c knowledge Input ,s mapped onto me grammar using m=s budt-~n syntact=c knowledge We nave chosen m=s approach for Plume ":'M a commercial restricted domam parser ~ because of ~ts advantages =n efficfency and robustness Let us take a simple example from a natural language interface, called NLVMS. thai we are developing under a 1 More 0:eccselv. P h j m e TM ,s m e n 4 m e ,)t l ne run-h l t le ~vstem TM assoc la lec l N~m L a n g u a g e Craf t an mlegra lerJ e n v l r o l l m e n l for m e o e v e t o o m e n l of na lura I l a n g u a g e ,n teHaces " h e PlUm? 10arser Nnlch t ransla{es Eng#lsl' l lil~UI qnto case t rame ,ns lances , .s a ma lo t comDone i I t ot tt~=s rur l t lme system The d iner malOr -,3111OG~te~H t rat is la les i r e case f rame ~nslance~ into aoDIica|lofl specifIC !anguaqes . in JlOOlhon to the Plume run-brae system, ta.guaqe Craft ,nc!uoes grammar d e v e l o p m e n t ~OOlS ,ncludlng -.1 -;lrH,:hJreO edl lOr .ln~l t rac ing ,1ha ,~ert.3rmance r n e a s u t e m e n l rOi)~S ~r~ln P l u m e Ji~a ~Jltq,iaqe Craft ate crOOuctS ,It C a r n e g i e G r o u p .~.d ,Jle u , t e l l t l y i,I re '~ l r l r leO r~tease Plume .]n~ Language CI,I f t It@ ,,,Id~,,Idr v'~ ,',t ]ot.1.+gle :3~,)HO ' nco toora fe~ l contract with Digital Equipment Corporation NLVMS ,s an tnterface to Digltal's VMS ~ operating system for './AX ~ computers 2 The Plume grammar for .th~s ,ntertace contains the follow=ng semantic caseframe 3 correspond=ng ¢o the copy command of VMS: [ *copy* :cf-type clausal :header copy :cases ( f i le-to-copy :filler *file* :positional Direct-Object) ( source :filler *directory* :marker from I out of) (destination :filler *file* I *directory* :marker to I into I in l onto) ] This defines a caseframe called "copy" w~th mree cases: file-to-copy, source, and destination The hie-to-copy case ,s filled by an oioiect of type "file" and appears =n the input as a direct ob lec t Source ,s filled 0y a "d~rectory" and should appear in me ~nput as a preposmonal phrase preceded or marked by the prepos,t~ons "from" or 'out of" Oestinat=on is filled by a "fi le" or "clirectory" and ~s marked by " to ' . " in to ' . or "onto" Finally the copy command itself is recognized by the header word ,ndicated above (by header) as " c o p y " Using mis caseframe. Plume can parse ,n0uts like: Copy fop Oar out ot [x/ ,nro [y~ From [x] to [yJ cooy fop oar too oar coDy /rom [x/ ro [y/ 2 V M S anO VAX are ¢raOemark5 of Olg=tal EQu.omen! CorDora l l on ]Th.s is a s.npiltleO .:e,slols ,~t rne r.L~e,, ~.~ e .I..'~,.IIh/ ~ fne gralnmar.