% start S
# ############################
# Grammar Rules
# ############################

# S expansion rules
S -> NP VP
S -> S Conj S

# NP expansion rules
NP -> PN
NP -> PropN
NP -> N
NP -> Det N
NP -> Digit Digit
NP -> NP PP
NP -> NP RelClause

# VP expansion rules
VP -> V
VP -> VP NP
VP -> VP Adj
VP -> VP PP
VP -> VP Adv

# misc expansion rules
PP -> Prep NP
RelClause -> That VP

# ############################
# Lexical Rules
# ############################

N -> 'stench' | 'breeze' | 'glitter' | 'nothing' | 'agent' 
N -> 'wumpus' | 'pit' | 'pits' | 'gold' | 'east'

V -> 'is' | 'see' | 'smell' | 'shoot' | 'feel' | 'stinks' | 'go'
V -> 'grab' | 'carry' | 'kill' | 'turn'

Adj -> 'right' | 'left' | 'east' | 'dead' | 'back' | 'smelly'

Adv -> 'here' | 'there' | 'nearby' | 'ahead' | 'right' | 'left' 
Adv ->  'east' | 'south' | 'back'

PN -> 'me' | 'you' | 'I' | 'it'

PropN -> 'John' | 'Mary' | 'Boston' | 'UCB' | 'Aristotle'

Det -> 'the' | 'a' | 'an'

Prep -> 'to' | 'in' | 'on' | 'near'

Conj -> 'and' | 'or' | 'but'

Digit -> '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'

That -> 'that'