patrikvalkovic/grammpy

grammpy's Issues

Problems with Chomsky Normal Form

Hello, I tried to use this library in my project, but found something interesting. According to wiki, grammar in Chomsky Normal form can't has starting nonterminal at the right side of any rule, also there can be rule S -> eps only if S is starting nonterminal. I tested your library on test S -> a S b S | eps, and found that if i creating new grammar by using transform_to_chomsky_normal_form, i found that new grammar has rules which looks like A -> S B, but i think, there shouldn't be these rules. So, i think that this algorithm doesn't work properly, or, maybe, it returns grammar in reduced CNF. Also maybe I did something wrong, so could you do the same test, please, to get sure I understood what this function should do

Same hash

Solve situation, when more teminals/nonterminals/rules have same hash value.