tree-sitter/todo.md

TODO

Handling ambiguity (GLR)

• Add a simple way to specify syntactic ambiguity resolutions in the Grammar (e.g. 'prefer declarations to statements' in C), similar to bison's dprec construct.
• Optimize the lexical DFA so that all compatible starting lex states are merged. Then, when the parse stack has multiple heads, check at runtime that each head's state corresponds to the same starting lex state.

Runtime System

• Don't automatically reparse on every edit; expose a separate function for explicitly reparsing, so that multiple related edits can be made cheaply.
• Refactoring: make separate symbol for unexpected characters than for interior error nodes.

Testing / Quality

• Start running the clang-analyzer on the codebase on Travis-CI.
• Use the Valgrind leak checker to fix the memory leaks in the runtime library.
• Randomize the editing in the language tests, using a seed that can be specified in order to reproduce failures.

Ubiquitous token handling

• Fix the unintuitive tree that results when ubiquitous tokens are last child of their parent node.

Error handling

• Use information about nesting depth of tokens like '(' and ')' to make error recovery more accurate.

Grammar Features

• Regexp assertions
  • '^'
  • '$'
  • '\b'
• Composing languages
  • Rule for referencing named grammar
  • Grammar registry object in runtime
  • Parsing returns control to parent language
• Indentation tokens

Performance

• Optimize grammar compilation