Parsing Free Word Order Languages In Prolog

The P r o l o g p r o g r a m m i n g l anguage a l lows the u s e r to w r i t e p o w e r f u l p a r s e r s in the fo rm of m e t a m o r p h o s i s g r a m m a r s . H o w e v e r , the m e t a m o r p h o s i s g r a m m a r s , as de f ined by C o l m e r a u e r 2 , h a v e to s p e c i f y s t r i c t l y the o r d e r of t e r m i n a l and n o n t e r m i n a l s y m b o l s . A m o d i f i c a t i o n of P r o l o g h a s b e e n imp lemented which a l l ows " f loa t ing t e r m i n a l s " to be included in a metamorphosis grammar together with some information enabling to coritrol the search for such a terminal in the unprocessed part of the input. The modification is illustrated by several examples from the Polish language and some open questions are discussed.