def demo():
"""
A demonstration showing how C{Grammar}s can be created and used.
"""
from nltk import cfg
# Create some nonterminals
S, NP, VP, PP = cfg.nonterminals('S, NP, VP, PP')
N, V, P, Det = cfg.nonterminals('N, V, P, Det')
VP_slash_NP = VP/NP
print 'Some nonterminals:', [S, NP, VP, PP, N, V, P, Det, VP/NP]
print ' S.symbol() =>', `S.symbol()`
print
print cfg.Production(S, [NP])
# Create some Grammar Productions
grammar = cfg.parse_grammar("""
S -> NP VP
PP -> P NP
NP -> Det N
NP -> NP PP
VP -> V NP
VP -> VP PP
Det -> 'a'
Det -> 'the'
N -> 'dog'
N -> 'cat'
V -> 'chased'
V -> 'sat'
P -> 'on'
P -> 'in'
""")
print 'A Grammar:', `grammar`
print ' grammar.start() =>', `grammar.start()`
print ' grammar.productions() =>',
# Use string.replace(...) is to line-wrap the output.
print `grammar.productions()`.replace(',', ',\n'+' '*25)
print
def demo():
"""
A demonstration showing how C{Grammar}s can be created and used.
"""
from nltk import cfg
# Create some nonterminals
S, NP, VP, PP = cfg.nonterminals('S, NP, VP, PP')
N, V, P, Det = cfg.nonterminals('N, V, P, Det')
VP_slash_NP = VP / NP
print 'Some nonterminals:', [S, NP, VP, PP, N, V, P, Det, VP / NP]
print ' S.symbol() =>', ` S.symbol() `
print
print cfg.Production(S, [NP])
# Create some Grammar Productions
grammar = cfg.parse_grammar("""
S -> NP VP
PP -> P NP
NP -> Det N
NP -> NP PP
VP -> V NP
VP -> VP PP
Det -> 'a'
Det -> 'the'
N -> 'dog'
N -> 'cat'
V -> 'chased'
V -> 'sat'
P -> 'on'
P -> 'in'
""")
print 'A Grammar:', ` grammar `
print ' grammar.start() =>', ` grammar.start() `
print ' grammar.productions() =>',
# Use string.replace(...) is to line-wrap the output.
print ` grammar.productions() `.replace(',', ',\n' + ' ' * 25)
print
def main():
sentence = 'The quick brown fox jumped over the lazy dog'
grammar = cfg.parse_grammar(read('demo.cfg'))
# load from pickle so it's faster
tagger = pickle.load(open('demo_tagger.pickle'))
tagged_chart_parse(sentence, grammar, tagger)
def main():
sentence = 'The quick brown fox jumped over the lazy dog'
grammar = cfg.parse_grammar(read('demo.cfg'))
# load from pickle so it's faster
tagger = pickle.load(open('demo_tagger.pickle'))
tagged_chart_parse(sentence, grammar, tagger)
