Alternations optimization #141
Open
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
We can go further than just literals, consider |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
In theory this speeds up regex containing hundreds of alternations (see #138). How? the first state contains a state per alternation; the optimization reduces the number of alternations (at the very least the outer one), so the first state will be capped to [a-zA-Z-0-9] ( symbols) states in the case of ASCII, so 1K initial states will get reduced to ~50. For find all this matters a lot because it tries to match the initial states to every input character.
The description is in this gist https://gist.github.com/nitely/745c8cabdf06ba2d37f8cf5cda3aea5f
This is just a PoC, though. I'm just optimizing the simplest case, since it should speed up #138
it's also a (broken) WIP that cannot even be tested.