
; Grammar source file

; Rule format is:-

; <rule>	::= ( <lhs> . <rhs> )
; <lhs>		::= <symbol>
; <rhs>		::= <nil> | ( <seq> )
; <seq>		::= <node> | <node> <seq> 
; <node>	::= <self> | <alts> | <star> | <opts>
; <self>	::= ( self . <category> )
; <alts>	::= ( alts . <rhs> ... <rhs> )
; <star>	::= ( star . <rhs> )
; <opts>	::= ( opts . <rhs> )

; <category>	::= ( <symbol> . <features> )
; <features>	::= <nil> | <feature> ... <feature>
; <feature>	::= <symbol> | ( <function> . <value> )
; <function>	::= ( <variable> ) | ( <variable> <symbol> ... <symbol> )
; <variable>	::= up | down
; <value>	::= <function> | <symbol> | <number>


(SP (SELF NP) (SELF VP) (SELF PP)) 
(SP (SELF NP) (SELF VP)) 