# I'm reworking this.  Great thanks is due to "Essentials of English",
# formerly "Essentials of Effective Writing", by Hopper, Gale, Foote
# and Griffith, published by Barron's.  I used the fourth edition,
# though I expect the other editions are just fine too.  I refer to it
# in the comments as 'EoE'.                             - angelbob

# This is really just the end of the grammar.  Before this, Phantasmal
# starts with the whitespace rule, some autogenerated part-of-speech
# token rules, the other basic token rules (see nl_tokens.dpd), and a
# bad-token rule.

# The autogenerated rules just categorize various words (like "lamp",
# "checkered", "fast", "take", etc) by what parts of speech (like
# noun, adjective, transitive verb, etc) they are.  Each overlap of
# categories (is a noun, isn't an adverb, etc) gets an autogenerated
# category.

# Later we may autogenerate the rules for each part of speech below,
# just to take more repetitive bits out of the grammar file.  Besides,
# that section's going to double in size every time we add a part of
# speech.  Autogenerating would let us remove nonexistent categories
# rather than stubbing them out.

### Start of non-token rules

# This is the start token
line: 

# A line of input is called 'line'.  Lines can consist of one or more
# sentences.  A sub_line is just one or more consecutive sentences,
# each with punctuation at the end.  Each sentence is an independent
# action.

line: sentence 
line: sub_line 
line: sub_line sentence 


# Sub_line is defined here as above.  It's just one or more sentences,
# each with command-ending punctuation (like a period or semicolon) at
# the end.  Note that commas don't count as command-ending
# punctuation.

sub_line: sentence punctuation 
sub_line: sub_line sentence punctuation 


# Sentences can have one or more independent clauses, which are
# treated like separate sentences for the sake of the MUD.

sentence: indep_clause
#sentence: sentence 'and' indep_clause
#sentence: sentence 'but' indep_clause

# Independent clauses -- the basic action.  Usually each clause is
# converted into one action, though there may be exceptions.

indep_clause: iverb            ? iclause_iverb
indep_clause: tverb np         ? iclause_tverb_np
#indep_clause: tverb pp
#indep_clause: tverb np pp
#indep_clause: tverb pp pp

# Plural noun phrases ("the cat and the girl") will eventually go
# here.  That's why we need a "noun phrase right" (npr) which can
# be parsed unambiguously.
np: npr
#np: np noun_conjunction npr

# Unambiguous definitions of noun phrases.  'npr' stands for noun
# phrase right-side, since this is where it appears in the noun phrase
# rules.  An npr is a simple noun phrase, and an 'np' is one or more
# nprs joined by conjunctions.
#
# Eventually we'll add rules about things like pronouns here.
npr: adj_noun     ? npr_adj_noun
npr: det adj_noun ? npr_det_adj_noun

# adj_noun is zero or more adjectives followed by a noun
adj_noun: adjp noun

# An adjp is zero or more adjectives
adjp:
adjp: adjp adjective

# Determiners, including articles.  Eventually things like possessives
# will go here.
det: article