Method visit_pre

regex/regex-syntax/src/ast/visitor.rs:48–50

This method is called on an `Ast` before descending into child `Ast` nodes.

(&mut self, _ast: &Ast)

    /// This method is called on an `Ast` before descending into child `Ast`
    /// nodes.
    fn visit_pre(&mut self, _ast: &Ast) -> Result<(), Self::Err> {
        Ok(())
    }

    /// This method is called on an `Ast` after descending all of its child
    /// `Ast` nodes.