Method visit_columns

src/sql/src/plan/hir.rs:2289–2300

Visits the column references in this relation expression. The `depth` argument should indicate the subquery nesting depth of the expression, which will be incremented when entering the RHS of a join or a subquery and presented to the supplied function `f`.

(&self, depth: usize, f: &mut F)

    /// which will be incremented when entering the RHS of a join or a subquery and
    /// presented to the supplied function `f`.
    pub fn visit_columns<F>(&self, depth: usize, f: &mut F)
    where
        F: FnMut(usize, &ColumnRef),
    {
        #[allow(deprecated)]
        let _ = self.visit_scalar_expressions(depth, &mut |e: &HirScalarExpr,
                                                           depth: usize|
         -> Result<(), ()> {
            e.visit_columns(depth, f);
            Ok(())
        });
    }

    #[deprecated = "Redefine this based on the `Visit` and `VisitChildren` methods."]
    /// Like `visit_columns`, but permits mutating the column references.