freshtonic commented on issue #934: URL: https://github.com/apache/datafusion-sqlparser-rs/issues/934#issuecomment-2841882050
@ramnes oh and one more thing that's very important. For workloads such as analysing an AST (in my case, deriving type information for a subset of node types) a `Visitor` implementation has to be able to associate information with AST nodes, so an implementation would have, say, a field like `derived_node_info: HashMap<&Expr, SomeDerivedInfo>`. The problem is that `&Expr` _must_ have a lifetime and that lifetime must be at least as long as the parsed AST lasts. That means the `Visitor` trait has to have some lifetime associated with the trait itself (e.g. `Visitor<'ast>`) and the enter/exit methods must use that lifetime for the node references, e.g. `fn enter(&mut self, node: &'ast N) ...`. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
