Current version: 2.0.0
Package for representing formal grammars. Contains algorithms to work with a grammars and parse them.
If you are using pip, simple run following command.
pip install grammpy
You can install the package from the repository as well.
git clone https://github.com/PatrikValkovic/grammpy.git
cd grammpy
python setup.py install
Defining a grammar doesn't require special tools anymore. All what you need is just a IDE and you have the full support.
Let's define grammar using standard Python objects instead.
from grammpy import *
from grammpy.transforms import ContextFree, InverseContextFree
from grammpy.parsers import cyk
class Number:
def __init__(self, value):
self.value = value
def __hash__(self):
return hash(Number)
class PlusNonterminal(Nonterminal):
@property
def value(self):
return self.to_rule.get_value()
class PlusRule(Rule):
rule = ([PlusNonterminal], [PlusNonterminal, '+', PlusNonterminal])
def get_value(self):
child1 = self.to_symbols[0]
child2 = self.to_symbols[2]
return child1.value + child2.value
class RewriteRule(Rule):
fromSymbol = PlusNonterminal
toSymbol = Number
def get_value(self):
return self.to_symbols[0].s.value
g = Grammar(terminals=[Number, '+'],
nonterminals=[PlusNonterminal],
rules=[PlusRule, RewriteRule],
start_symbol=PlusNonterminal)
ContextFree.prepare_for_cyk(g, inplace=True)
root = cyk(g, [Number(5), '+', Number(3), '+' , Number(8)])
root = InverseContextFree.reverse_cyk_transforms(root)
assert root.value == 16You can read more about the library in the doc directory.
You can view some examples in the examples directory.
Version: 2.0.0
Author: Patrik Valkovič
Licence: MIT