mz_sql/
ast.rs

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1// Copyright Materialize, Inc. and contributors. All rights reserved.
2//
3// Use of this software is governed by the Business Source License
4// included in the LICENSE file.
5//
6// As of the Change Date specified in that file, in accordance with
7// the Business Source License, use of this software will be governed
8// by the Apache License, Version 2.0.
9
10//! SQL abstract syntax tree.
11
12use mz_sql_parser::ast::visit::Visit;
13pub use mz_sql_parser::ast::*;
14pub mod transform;
15
16/// A visitor that determines if a node is constant (does not contain references to external
17/// objects).
18#[derive(Debug)]
19pub struct ConstantVisitor {
20    pub constant: bool,
21}
22
23impl ConstantVisitor {
24    /// Whether the insert source is constant.
25    pub fn insert_source<T: AstInfo>(node: &InsertSource<T>) -> bool {
26        let mut visitor = Self { constant: true };
27        visitor.visit_insert_source(node);
28        visitor.constant
29    }
30}
31
32impl<'ast, T: AstInfo> Visit<'ast, T> for ConstantVisitor {
33    fn visit_set_expr(&mut self, node: &'ast SetExpr<T>) {
34        if matches!(node, SetExpr::Show(_) | SetExpr::Table(_)) {
35            self.constant = false;
36        }
37        visit::visit_set_expr(self, node);
38    }
39
40    fn visit_table_factor(&mut self, node: &'ast TableFactor<T>) {
41        // It's possible a table reference is referencing some constant table defined within the
42        // query, but we don't want the AST to have to figure that out yet. If that's required, the
43        // statement must be planned instead.
44        if matches!(node, TableFactor::Table { .. }) {
45            self.constant = false;
46        }
47    }
48}
mz_sql/ast.rs

mz_sql/
ast.rs
