A Student-Oriented Natural Language Environment For Learning LISP

A computer-based i n s t r u c t i o n a l env i ronment f o r s t u d e n t s l e a r n i n g LISP i s d e s c r i b e d . I t s des ign i n c l u d e s a LISP I n t e r p r e t e r w i t h an extended e r r o r h a n d l i n g c a p a b i l i t y f o r e v a l u a t i n g f u n c t i o n s w r i t t e n by s t u d e n t s . S tudents can ask q u e s t i o n s in n a t u r a l language about LISP in gene ra l and con c e r n i n g s p e c i f i c LISP f u n c t i o n s which they have d e f i n e d . A fuzzy pa rse r i n t e r p r e t s the s tuden t reques ts and b u i l d s a LISP f u n c t i o n wh ich ope ra tes on a semant ic ne twork to de te rmine i t s response. I n t r o d u c t i o n A s a n a p p l i c a t i o n a rea o f A r t i f i c i a l I n t e l l i gence, computer -a ided i n s t r u c t i o n ( C A I ) , has r e c e i v e d c o n s i d e r a b l e i n t e r e s t ( 1 ) . C a r b o n e l l ' s SCHOLAR (2) is perhaps the bes t known example of a " m i x e d i n i t i a t i v e " CAI sys tem. Through SCHOLAR, s t u d e n t s can ask q u e s t i o n s about concepts r e l e v a n t to the geography o f South Amer ica . Koffman and B loun t (3) have developed a s y s tem to teach machinelanguage programming. Th i s system can genera te programming prob lems, and moni t o r and a s s i s t s t uden t s i n cod ing t h e i r s o l u t i o n programs. Th i s system conca tena tes a sma l l se t o f prob lem p r i m i t i v e s and assoc ia ted s o l u t i o n r o u t i n e s i n o rde r t o c r e a t e and so l ve m e a n i n g f u l p r o gramming p rob lems. N a t u r a l language unde rs tand ing i s becoming more impo r t an t In CAI system. Many power fu l p a r se rs have been developed f o r v e r y e x t e n s i v e subBets o f E n g l i s h i n c l u d i n g Wood's pa rse r (A) and V l n o g r a d ' s PROGRAMMER ( 5 ) . These methods are b e g i n n i n g to be o f use f o r q u e s t i o n answer ing subsystems and f o r i n t e r p r e t i n g s tuden t responses . Of p a r t i c u l a r I n t e r e s t is the work done by Brown e t a l ( 6 ) . I t i s h i s s e m a n t l c a l l y d r i v e n fuzzy grammar t h a t has I n f l u e n c e d t h i s r e s e a r c h . Brown ana lyzed s tuden t scena r ios I n v o l v i n g e l e c t r o n i c c i r c u i t t r o u b l e s h o o t i n g and d i scove red t h a t the concepts and i tems d iscussed f e l l I n t o s m a l l numbers o f semant ic g roup ings or c a t e g o r i e s . These i n c l u d e d : measurements, c o n t r o l s e t t i n g s , c i r c u i t e l emen ts , and c i r c u i t l o c a t i o n s r e l a t i v e t o the e l e c t r o n i c c i r c u i t . The parse was then accompl ished by a n t i c i p a t i n g and l o o k i n g f o r phrases wh ich matched these semant ic c a t e g o r i e s where they m igh t be a p p r o p r i a t e . The p a r s e r ' s f u z z l n e s s stems f rom the f a c t t h a t words t h a t a r e not unders tood can be sk ipped ove r . Teaching a programming language embraces two ma jo r t a s k s . One is p r e s e n t i n g new m a t e r i a l In an o r d e r l y c o n t r o l l e d f a s h i o n . The o the r i n v o l v e s making a v a i l a b l e a f r i e n d l y , i n f o r m a t i v e e n v i r o n ment t h a t a l l o w s e x p e r i m e n t a t i o n , and t h a t can r e cogn ize e r r o r s and m isconcep t ions and p o i n t them o u t . W i t h ISLE ( I n t e r a c t i v e Student LISP E n v i r o n ment) we have concen t ra ted on t h i s second i tem by d e v e l o p i n g a computer-based envi ronment f o r LISP. The system knows about the s t r u c t u r e and semant ics of t he LISP language and can answer ques t i ons about LISP da ta s t r u c t u r e s , concepts and f u n c t i o n s ; bo th those f u n c t i o n s d e f i n e d by the s tuden t and the p r i m i t i v e s i n t e r n a l t o the system. As an example cons ide r the f o l l o w i n g d i a l o g u e : N o t i c e t h a t q u e s t i o n s are answered W i t h a complete s ta tement to avo id any a m b i g u i t y , a l s o no te the use o f the pronoun i t by the s t u d e n t . Some l i m i t e d anaphor ic r e f e r e n c e Is p e r m i t t e d by the system to a l l o w a more n a t u r a l d i a l o g u e .