Parsetron - A natural language semantic parser
A natural language semantic parser
Installation
pip install parsetron
Parsetron is tested under Python 2.7 and Pypy. It doesn't support Python 3 yet.
Documentation and Tutorial
Quick Start
The following is a grammar that parses natural language instruction on lights:
from parsetron import Set, Regex, Optional, OneOrMore, Grammar, RobustParser
class LightGrammar(Grammar):
action = Set(['change', 'flash', 'set', 'blink'])
light = Set(['top', 'middle', 'bottom'])
color = Regex(r'(red|yellow|blue|orange|purple|...)')
times = Set(['once', 'twice', 'three times']) | Regex(r'\d+ times')
one_parse = action + light + Optional(times) + color
GOAL = OneOrMore(one_parse)
@staticmethod
def test():
parser = RobustParser((LightGrammar()))
sents = [
"set my top light to red",
"set my top light to red and change middle light to yellow",
"set my top light to red and change middle light to yellow and "
"flash bottom light twice in blue"
]
for sent in sents:
tree, result = parser.parse(sent)
assert result.one_parse[0].color == 'red'
print '"%s"' % sent
print "parse tree:"
print tree
print "parse result:"
print result
printDependencies
None. Parsetron is a single parsetron.py file.
Parsetron is inspired by pyparsing.
Grammar Modules
Parsetron supports modularized grammars: each grammar focuses on an individual small domain and can be imported via, for instance:
from parsetron.grammars.colors import ColorsGrammar
class YourCustomizedGrammar(Grammar):
color = ColorsGrammar.GOALYou are welcome to contribute your own grammar here (under
parsetron.grammars). Send us a pull request!
Development
fork this repository
install dev-specific packages:
pip install -r requirements.txt
then make your changes and follow the
Makefile.
TODO
- [ ] Python 3 compatible
- [ ] Unicode support