Add serde support to AST structs and enums (#196)

Apply serde to AST structs and enums to be serializable/deserializable.
serde support is optional, can be activated by feature named "serde".

Cargo.toml

@@ -19,8 +19,9 @@ name = "sqlparser"
 path = "src/lib.rs"
 
 [dependencies]
-bigdecimal = { version = "0.1.0", optional = true }
+bigdecimal = { version = "0.1.0", features = ["serde"], optional = true }
 log = "0.4.5"
+serde = { version = "1.0", features = ["derive"], optional = true }
 
 [dev-dependencies]
 simple_logger = "1.0.1"

src/ast/data_type.rs

@@ -11,10 +11,13 @@
 // limitations under the License.
 
 use super::ObjectName;
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 use std::fmt;
 
 /// SQL data types
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum DataType {
     /// Fixed-length character type e.g. CHAR(10)
     Char(Option<u64>),

src/ast/ddl.rs

@@ -13,10 +13,13 @@
 //! AST types specific to CREATE/ALTER variants of [Statement]
 //! (commonly referred to as Data Definition Language, or DDL)
 use super::{display_comma_separated, DataType, Expr, Ident, ObjectName};
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 use std::fmt;
 
 /// An `ALTER TABLE` (`Statement::AlterTable`) operation
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum AlterTableOperation {
     /// `ADD <table_constraint>`
     AddConstraint(TableConstraint),
@@ -36,6 +39,7 @@ impl fmt::Display for AlterTableOperation {
 /// A table-level constraint, specified in a `CREATE TABLE` or an
 /// `ALTER TABLE ADD <constraint>` statement.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum TableConstraint {
     /// `[ CONSTRAINT <name> ] { PRIMARY KEY | UNIQUE } (<columns>)`
     Unique {
@@ -95,6 +99,7 @@ impl fmt::Display for TableConstraint {
 
 /// SQL column definition
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct ColumnDef {
     pub name: Ident,
     pub data_type: DataType,
@@ -129,6 +134,7 @@ impl fmt::Display for ColumnDef {
 /// non-constraint options, lumping them all together under the umbrella of
 /// "column options," and we allow any column option to be named.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct ColumnOptionDef {
     pub name: Option<Ident>,
     pub option: ColumnOption,
@@ -143,6 +149,7 @@ impl fmt::Display for ColumnOptionDef {
 /// `ColumnOption`s are modifiers that follow a column definition in a `CREATE
 /// TABLE` statement.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum ColumnOption {
     /// `NULL`
     Null,
@@ -220,6 +227,7 @@ fn display_constraint_name<'a>(name: &'a Option<Ident>) -> impl fmt::Display + '
 ///
 /// Used in foreign key constraints in `ON UPDATE` and `ON DELETE` options.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum ReferentialAction {
     Restrict,
     Cascade,

src/ast/mod.rs

@@ -18,6 +18,8 @@ mod operator;
 mod query;
 mod value;
 
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 use std::fmt;
 
 pub use self::data_type::DataType;
@@ -71,6 +73,7 @@ where
 
 /// An identifier, decomposed into its value or character data and the quote style.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Ident {
     /// The value of the identifier without quotes.
     pub value: String,
@@ -127,6 +130,7 @@ impl fmt::Display for Ident {
 
 /// A name of a table, view, custom type, etc., possibly multi-part, i.e. db.schema.obj
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct ObjectName(pub Vec<Ident>);
 
 impl fmt::Display for ObjectName {
@@ -141,6 +145,7 @@ impl fmt::Display for ObjectName {
 /// (e.g. boolean vs string), so the caller must handle expressions of
 /// inappropriate type, like `WHERE 1` or `SELECT 1=1`, as necessary.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum Expr {
     /// Identifier e.g. table name or column name
     Identifier(Ident),
@@ -308,6 +313,7 @@ impl fmt::Display for Expr {
 
 /// A window specification (i.e. `OVER (PARTITION BY .. ORDER BY .. etc.)`)
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct WindowSpec {
     pub partition_by: Vec<Expr>,
     pub order_by: Vec<OrderByExpr>,
@@ -353,6 +359,7 @@ impl fmt::Display for WindowSpec {
 /// Note: The parser does not validate the specified bounds; the caller should
 /// reject invalid bounds like `ROWS UNBOUNDED FOLLOWING` before execution.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct WindowFrame {
     pub units: WindowFrameUnits,
     pub start_bound: WindowFrameBound,
@@ -364,6 +371,7 @@ pub struct WindowFrame {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum WindowFrameUnits {
     Rows,
     Range,
@@ -398,6 +406,7 @@ impl FromStr for WindowFrameUnits {
 
 /// Specifies [WindowFrame]'s `start_bound` and `end_bound`
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum WindowFrameBound {
     /// `CURRENT ROW`
     CurrentRow,
@@ -422,6 +431,7 @@ impl fmt::Display for WindowFrameBound {
 /// A top-level statement (SELECT, INSERT, CREATE, etc.)
 #[allow(clippy::large_enum_variant)]
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum Statement {
     /// SELECT
     Query(Box<Query>),
@@ -766,6 +776,7 @@ impl fmt::Display for Statement {
 
 /// SQL assignment `foo = expr` as used in SQLUpdate
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Assignment {
     pub id: Ident,
     pub value: Expr,
@@ -779,6 +790,7 @@ impl fmt::Display for Assignment {
 
 /// A function call
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Function {
     pub name: ObjectName,
     pub args: Vec<Expr>,
@@ -805,6 +817,7 @@ impl fmt::Display for Function {
 
 /// External table's available file format
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum FileFormat {
     TEXTFILE,
     SEQUENCEFILE,
@@ -856,6 +869,7 @@ impl FromStr for FileFormat {
 /// A `LISTAGG` invocation `LISTAGG( [ DISTINCT ] <expr>[, <separator> ] [ON OVERFLOW <on_overflow>] ) )
 /// [ WITHIN GROUP (ORDER BY <within_group1>[, ...] ) ]`
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct ListAgg {
     pub distinct: bool,
     pub expr: Box<Expr>,
@@ -892,6 +906,7 @@ impl fmt::Display for ListAgg {
 
 /// The `ON OVERFLOW` clause of a LISTAGG invocation
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum ListAggOnOverflow {
     /// `ON OVERFLOW ERROR`
     Error,
@@ -925,6 +940,7 @@ impl fmt::Display for ListAggOnOverflow {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum ObjectType {
     Table,
     View,
@@ -944,6 +960,7 @@ impl fmt::Display for ObjectType {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct SqlOption {
     pub name: Ident,
     pub value: Value,
@@ -956,6 +973,7 @@ impl fmt::Display for SqlOption {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum TransactionMode {
     AccessMode(TransactionAccessMode),
     IsolationLevel(TransactionIsolationLevel),
@@ -972,6 +990,7 @@ impl fmt::Display for TransactionMode {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum TransactionAccessMode {
     ReadOnly,
     ReadWrite,
@@ -988,6 +1007,7 @@ impl fmt::Display for TransactionAccessMode {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum TransactionIsolationLevel {
     ReadUncommitted,
     ReadCommitted,
@@ -1008,6 +1028,7 @@ impl fmt::Display for TransactionIsolationLevel {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum ShowStatementFilter {
     Like(String),
     Where(Expr),
@@ -1024,6 +1045,7 @@ impl fmt::Display for ShowStatementFilter {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum SetVariableValue {
     Ident(Ident),
     Literal(Value),

src/ast/operator.rs

@@ -10,10 +10,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 use std::fmt;
 
 /// Unary operators
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum UnaryOperator {
     Plus,
     Minus,
@@ -32,6 +35,7 @@ impl fmt::Display for UnaryOperator {
 
 /// Binary operators
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum BinaryOperator {
     Plus,
     Minus,

src/ast/query.rs

@@ -11,10 +11,13 @@
 // limitations under the License.
 
 use super::*;
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 
 /// The most complete variant of a `SELECT` query expression, optionally
 /// including `WITH`, `UNION` / other set operations, and `ORDER BY`.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Query {
     /// WITH (common table expressions, or CTEs)
     pub ctes: Vec<Cte>,
@@ -55,6 +58,7 @@ impl fmt::Display for Query {
 /// A node in a tree, representing a "query body" expression, roughly:
 /// `SELECT ... [ {UNION|EXCEPT|INTERSECT} SELECT ...]`
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum SetExpr {
     /// Restricted SELECT .. FROM .. HAVING (no ORDER BY or set operations)
     Select(Box<Select>),
@@ -92,6 +96,7 @@ impl fmt::Display for SetExpr {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum SetOperator {
     Union,
     Except,
@@ -112,6 +117,7 @@ impl fmt::Display for SetOperator {
 /// appear either as the only body item of an `SQLQuery`, or as an operand
 /// to a set operation like `UNION`.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Select {
     pub distinct: bool,
     /// MSSQL syntax: `TOP (<N>) [ PERCENT ] [ WITH TIES ]`
@@ -156,6 +162,7 @@ impl fmt::Display for Select {
 /// of the columns returned by the query. The parser does not validate that the
 /// number of columns in the query matches the number of columns in the query.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Cte {
     pub alias: TableAlias,
     pub query: Query,
@@ -169,6 +176,7 @@ impl fmt::Display for Cte {
 
 /// One item of the comma-separated list following `SELECT`
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum SelectItem {
     /// Any expression, not followed by `[ AS ] alias`
     UnnamedExpr(Expr),
@@ -192,6 +200,7 @@ impl fmt::Display for SelectItem {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct TableWithJoins {
     pub relation: TableFactor,
     pub joins: Vec<Join>,
@@ -209,6 +218,7 @@ impl fmt::Display for TableWithJoins {
 
 /// A table name or a parenthesized subquery with an optional alias
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum TableFactor {
     Table {
         name: ObjectName,
@@ -274,6 +284,7 @@ impl fmt::Display for TableFactor {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct TableAlias {
     pub name: Ident,
     pub columns: Vec<Ident>,
@@ -290,6 +301,7 @@ impl fmt::Display for TableAlias {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Join {
     pub relation: TableFactor,
     pub join_operator: JoinOperator,
@@ -355,6 +367,7 @@ impl fmt::Display for Join {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum JoinOperator {
     Inner(JoinConstraint),
     LeftOuter(JoinConstraint),
@@ -368,6 +381,7 @@ pub enum JoinOperator {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum JoinConstraint {
     On(Expr),
     Using(Vec<Ident>),
@@ -376,6 +390,7 @@ pub enum JoinConstraint {
 
 /// An `ORDER BY` expression
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct OrderByExpr {
     pub expr: Expr,
     /// Optional `ASC` or `DESC`
@@ -402,6 +417,7 @@ impl fmt::Display for OrderByExpr {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Offset {
     pub value: Expr,
     pub rows: OffsetRows,
@@ -415,6 +431,7 @@ impl fmt::Display for Offset {
 
 /// Stores the keyword after `OFFSET <number>`
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum OffsetRows {
     /// Omitting ROW/ROWS is non-standard MySQL quirk.
     None,
@@ -433,6 +450,7 @@ impl fmt::Display for OffsetRows {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Fetch {
     pub with_ties: bool,
     pub percent: bool,
@@ -452,6 +470,7 @@ impl fmt::Display for Fetch {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Top {
     /// SQL semantic equivalent of LIMIT but with same structure as FETCH.
     pub with_ties: bool,
@@ -472,6 +491,7 @@ impl fmt::Display for Top {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct Values(pub Vec<Vec<Expr>>);
 
 impl fmt::Display for Values {

src/ast/value.rs

@@ -12,10 +12,13 @@
 
 #[cfg(feature = "bigdecimal")]
 use bigdecimal::BigDecimal;
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 use std::fmt;
 
 /// Primitive SQL values such as number and string
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum Value {
     /// Numeric literal
     #[cfg(not(feature = "bigdecimal"))]
@@ -116,6 +119,7 @@ impl fmt::Display for Value {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum DateTimeField {
     Year,
     Month,