-
Notifications
You must be signed in to change notification settings - Fork 12
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Implement ε-rules (empty rules) #6
Labels
Milestone
Comments
Here is an implementation of Earley that handles Epsilon transition: https://github.com/tomerfiliba/tau/blob/master/Earley.java Is it possible to port the feature here? |
It's possible, but not as easily as in the example you give. Dealing with probabilities complicates the issue considerably. Stolcke describes how to it in his paper. I welcome any work on it, but am not planning to implement it myself. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
The parser currently can't handle rules of the form
where ε is the empty string.
See section 4.7 Null Productions on page 19 of Stolcke's paper.
We have the choice of extending prediction and completion to work with ε-rules, but this is a bit complicated. Another possibility is to rewrite the grammar to eliminate these productions, described at the end of page 20, 4.7.4 Eliminating null productions.
Best to implement the simpler solution first, and implement the philosphically correct version later.
The text was updated successfully, but these errors were encountered: