TODO

Incremental parsing
- Add randomized editing to all language tests.
  - inserts
  - deletes
  - replaces
- Verify that tree remains the same after edit is undone.
- Verify that the tree's total size is as expected after each edit.
Ubiquitous token handling
- Fix the unintuitive tree that results when ubiquitous tokens are last child of their parent node.
Error handling
- Try to minimize size of error node by looking ahead a few tokens
Grammar Features
- Indentation tokens
- Regexp assertions
  - '^'
  - '$'
  - '\b'
- Composing languages
  - Rule for referencing named grammar
  - Grammar registry object in runtime
  - Parsing returns control to parent language
Performance
- Optimize grammar compilation
Grammars
- C
- Go
Query API
- closest(node name)
- find(node name)