Method visit_expr_mut

src/sql/src/plan/query.rs:6377–6439

(&mut self, expr: &mut Expr<Aug>)

    }

    fn visit_expr_mut(&mut self, expr: &mut Expr<Aug>) {
        let (disallowed_context, func) = match expr {
            Expr::Case { .. } => (Some("CASE"), None),
            Expr::HomogenizingFunction {
                function: HomogenizingFunction::Coalesce,
                ..
            } => (Some("COALESCE"), None),
            Expr::Function(func) if self.in_select_item => {
                // If we're in a SELECT list, replace table functions with a uuid identifier
                // and save the table func so it can be planned elsewhere.
                let mut table_func = None;
                if let Ok(item) = self.scx.get_item_by_resolved_name(&func.name) {
                    if let Ok(Func::Table { .. }) = item.func() {
                        if let Some(context) = self.table_disallowed_context.last() {
                            self.err = Some(sql_err!(
                                "table functions are not allowed in {} (function {})",
                                context,
                                func.name
                            ));
                            return;
                        }
                        table_func = Some(func.clone());
                    }
                }
                // Since we will descend into the table func below, don't add its own disallow
                // context here, instead use visit_function to set that.
                (None, table_func)
            }
            _ => (None, None),
        };
        if let Some(func) = func {
            // Since we are trading out expr, we need to visit the table func here.
            visit_mut::visit_expr_mut(self, expr);
            // Don't attempt to replace table functions with unsupported syntax.
            if let Function {
                name: _,
                args: _,
                filter: None,
                over: None,
                distinct: false,
            } = &func
            {
                // Identical table functions can be de-duplicated.
                let unique_id = self.id_gen.allocate_id();
                let id = self
                    .tables
                    .entry(func)
                    .or_insert_with(|| format!("table_func_{unique_id}"));
                // We know this is okay because id is is 11 characters + <=20 characters, which is
                // less than our max length.
                *expr = Expr::Identifier(vec![Ident::new_unchecked(id.clone())]);
            }
        }
        if let Some(context) = disallowed_context {
            self.table_disallowed_context.push(context);
        }

        visit_mut::visit_expr_mut(self, expr);