diff --git a/partiql-ast/api/partiql-ast.api b/partiql-ast/api/partiql-ast.api
index ac6ebdc2b..c74ffddad 100644
--- a/partiql-ast/api/partiql-ast.api
+++ b/partiql-ast/api/partiql-ast.api
@@ -5631,6 +5631,11 @@ public final class org/partiql/ast/v1/Ast {
 	public static final fun sort (Lorg/partiql/ast/v1/expr/Expr;Lorg/partiql/ast/v1/Order;Lorg/partiql/ast/v1/Nulls;)Lorg/partiql/ast/v1/Sort;
 }
 
+public abstract class org/partiql/ast/v1/AstEnum : org/partiql/ast/v1/AstNode {
+	public fun <init> ()V
+	public abstract fun code ()I
+}
+
 public abstract class org/partiql/ast/v1/AstNode {
 	public field tag Ljava/lang/String;
 	public fun <init> ()V
@@ -5737,7 +5742,7 @@ public abstract interface class org/partiql/ast/v1/AstVisitor {
 	public abstract fun visitTableRef (Lorg/partiql/ast/v1/FromTableRef;Ljava/lang/Object;)Ljava/lang/Object;
 }
 
-public class org/partiql/ast/v1/DataType : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/DataType : org/partiql/ast/v1/AstEnum {
 	public static final field BAG I
 	public static final field BIGINT I
 	public static final field BINARY_LARGE_OBJECT I
@@ -5859,19 +5864,21 @@ public class org/partiql/ast/v1/DataType : org/partiql/ast/v1/Enum {
 	public static fun USER_DEFINED (Lorg/partiql/ast/v1/IdentifierChain;)Lorg/partiql/ast/v1/DataType;
 	public static fun VARCHAR ()Lorg/partiql/ast/v1/DataType;
 	public static fun VARCHAR (I)Lorg/partiql/ast/v1/DataType;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun getLength ()Ljava/lang/Integer;
 	public fun getName ()Lorg/partiql/ast/v1/IdentifierChain;
 	public fun getPrecision ()Ljava/lang/Integer;
 	public fun getScale ()Ljava/lang/Integer;
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/DataType;
-	public static fun values ()[Lorg/partiql/ast/v1/DataType;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/DataType;
 }
 
-public class org/partiql/ast/v1/DatetimeField : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/DatetimeField : org/partiql/ast/v1/AstEnum {
 	public static final field DAY I
 	public static final field HOUR I
 	public static final field MINUTE I
@@ -5890,16 +5897,14 @@ public class org/partiql/ast/v1/DatetimeField : org/partiql/ast/v1/Enum {
 	public static fun TIMEZONE_MINUTE ()Lorg/partiql/ast/v1/DatetimeField;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/DatetimeField;
 	public static fun YEAR ()Lorg/partiql/ast/v1/DatetimeField;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/DatetimeField;
-	public static fun values ()[Lorg/partiql/ast/v1/DatetimeField;
-}
-
-public abstract interface class org/partiql/ast/v1/Enum {
-	public abstract fun code ()I
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/DatetimeField;
 }
 
 public class org/partiql/ast/v1/Exclude : org/partiql/ast/v1/AstNode {
@@ -6079,19 +6084,21 @@ public abstract class org/partiql/ast/v1/FromTableRef : org/partiql/ast/v1/AstNo
 	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 }
 
-public class org/partiql/ast/v1/FromType : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/FromType : org/partiql/ast/v1/AstEnum {
 	public static final field SCAN I
 	public static final field UNKNOWN I
 	public static final field UNPIVOT I
 	public static fun SCAN ()Lorg/partiql/ast/v1/FromType;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/FromType;
 	public static fun UNPIVOT ()Lorg/partiql/ast/v1/FromType;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/FromType;
-	public static fun values ()[Lorg/partiql/ast/v1/FromType;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/FromType;
 }
 
 public class org/partiql/ast/v1/GroupBy : org/partiql/ast/v1/AstNode {
@@ -6131,19 +6138,21 @@ public class org/partiql/ast/v1/GroupBy$Key$Builder {
 	public fun toString ()Ljava/lang/String;
 }
 
-public class org/partiql/ast/v1/GroupByStrategy : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/GroupByStrategy : org/partiql/ast/v1/AstEnum {
 	public static final field FULL I
 	public static final field PARTIAL I
 	public static final field UNKNOWN I
 	public static fun FULL ()Lorg/partiql/ast/v1/GroupByStrategy;
 	public static fun PARTIAL ()Lorg/partiql/ast/v1/GroupByStrategy;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/GroupByStrategy;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/GroupByStrategy;
-	public static fun values ()[Lorg/partiql/ast/v1/GroupByStrategy;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/GroupByStrategy;
 }
 
 public class org/partiql/ast/v1/Identifier : org/partiql/ast/v1/AstNode {
@@ -6184,7 +6193,7 @@ public class org/partiql/ast/v1/IdentifierChain$Builder {
 	public fun toString ()Ljava/lang/String;
 }
 
-public class org/partiql/ast/v1/JoinType : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/JoinType : org/partiql/ast/v1/AstEnum {
 	public static final field CROSS I
 	public static final field FULL I
 	public static final field FULL_OUTER I
@@ -6203,12 +6212,14 @@ public class org/partiql/ast/v1/JoinType : org/partiql/ast/v1/Enum {
 	public static fun RIGHT ()Lorg/partiql/ast/v1/JoinType;
 	public static fun RIGHT_OUTER ()Lorg/partiql/ast/v1/JoinType;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/JoinType;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/JoinType;
-	public static fun values ()[Lorg/partiql/ast/v1/JoinType;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/JoinType;
 }
 
 public class org/partiql/ast/v1/Let : org/partiql/ast/v1/AstNode {
@@ -6244,34 +6255,38 @@ public class org/partiql/ast/v1/Let$Builder {
 	public fun toString ()Ljava/lang/String;
 }
 
-public class org/partiql/ast/v1/Nulls : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/Nulls : org/partiql/ast/v1/AstEnum {
 	public static final field FIRST I
 	public static final field LAST I
 	public static final field UNKNOWN I
 	public static fun FIRST ()Lorg/partiql/ast/v1/Nulls;
 	public static fun LAST ()Lorg/partiql/ast/v1/Nulls;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/Nulls;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/Nulls;
-	public static fun values ()[Lorg/partiql/ast/v1/Nulls;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/Nulls;
 }
 
-public class org/partiql/ast/v1/Order : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/Order : org/partiql/ast/v1/AstEnum {
 	public static final field ASC I
 	public static final field DESC I
 	public static final field UNKNOWN I
 	public static fun ASC ()Lorg/partiql/ast/v1/Order;
 	public static fun DESC ()Lorg/partiql/ast/v1/Order;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/Order;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/Order;
-	public static fun values ()[Lorg/partiql/ast/v1/Order;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/Order;
 }
 
 public class org/partiql/ast/v1/OrderBy : org/partiql/ast/v1/AstNode {
@@ -6503,32 +6518,36 @@ public class org/partiql/ast/v1/SetOp$Builder {
 	public fun toString ()Ljava/lang/String;
 }
 
-public class org/partiql/ast/v1/SetOpType : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/SetOpType : org/partiql/ast/v1/AstEnum {
 	public static fun EXCEPT ()Lorg/partiql/ast/v1/SetOpType;
 	public static fun INTERSECT ()Lorg/partiql/ast/v1/SetOpType;
 	public static fun UNION ()Lorg/partiql/ast/v1/SetOpType;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/SetOpType;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/SetOpType;
-	public static fun values ()[Lorg/partiql/ast/v1/SetOpType;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/SetOpType;
 }
 
-public class org/partiql/ast/v1/SetQuantifier : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/SetQuantifier : org/partiql/ast/v1/AstEnum {
 	public static final field ALL I
 	public static final field DISTINCT I
 	public static final field UNKNOWN I
 	public static fun ALL ()Lorg/partiql/ast/v1/SetQuantifier;
 	public static fun DISTINCT ()Lorg/partiql/ast/v1/SetQuantifier;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/SetQuantifier;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/SetQuantifier;
-	public static fun values ()[Lorg/partiql/ast/v1/SetQuantifier;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/SetQuantifier;
 }
 
 public class org/partiql/ast/v1/Sort : org/partiql/ast/v1/AstNode {
@@ -7287,22 +7306,24 @@ public class org/partiql/ast/v1/expr/PathStep$Field : org/partiql/ast/v1/expr/Pa
 	public fun hashCode ()I
 }
 
-public class org/partiql/ast/v1/expr/Scope : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/expr/Scope : org/partiql/ast/v1/AstEnum {
 	public static final field DEFAULT I
 	public static final field LOCAL I
 	public static final field UNKNOWN I
 	public static fun DEFAULT ()Lorg/partiql/ast/v1/expr/Scope;
 	public static fun LOCAL ()Lorg/partiql/ast/v1/expr/Scope;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/expr/Scope;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/expr/Scope;
-	public static fun values ()[Lorg/partiql/ast/v1/expr/Scope;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/expr/Scope;
 }
 
-public class org/partiql/ast/v1/expr/SessionAttribute : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/expr/SessionAttribute : org/partiql/ast/v1/AstEnum {
 	public static final field CURRENT_DATE I
 	public static final field CURRENT_USER I
 	public static final field UNKNOWN I
@@ -7310,15 +7331,17 @@ public class org/partiql/ast/v1/expr/SessionAttribute : org/partiql/ast/v1/Enum
 	public static fun CURRENT_DATE ()Lorg/partiql/ast/v1/expr/SessionAttribute;
 	public static fun CURRENT_USER ()Lorg/partiql/ast/v1/expr/SessionAttribute;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/expr/SessionAttribute;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/expr/SessionAttribute;
-	public static fun values ()[Lorg/partiql/ast/v1/expr/SessionAttribute;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/expr/SessionAttribute;
 }
 
-public class org/partiql/ast/v1/expr/TrimSpec : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/expr/TrimSpec : org/partiql/ast/v1/AstEnum {
 	public static final field BOTH I
 	public static final field LEADING I
 	public static final field TRAILING I
@@ -7327,15 +7350,17 @@ public class org/partiql/ast/v1/expr/TrimSpec : org/partiql/ast/v1/Enum {
 	public static fun LEADING ()Lorg/partiql/ast/v1/expr/TrimSpec;
 	public static fun TRAILING ()Lorg/partiql/ast/v1/expr/TrimSpec;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/expr/TrimSpec;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/expr/TrimSpec;
-	public static fun values ()[Lorg/partiql/ast/v1/expr/TrimSpec;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/expr/TrimSpec;
 }
 
-public class org/partiql/ast/v1/expr/WindowFunction : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/expr/WindowFunction : org/partiql/ast/v1/AstEnum {
 	public static final field LAG I
 	public static final field LEAD I
 	public static final field UNKNOWN I
@@ -7343,15 +7368,17 @@ public class org/partiql/ast/v1/expr/WindowFunction : org/partiql/ast/v1/Enum {
 	public static fun LAG ()Lorg/partiql/ast/v1/expr/WindowFunction;
 	public static fun LEAD ()Lorg/partiql/ast/v1/expr/WindowFunction;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/expr/WindowFunction;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/expr/WindowFunction;
-	public static fun values ()[Lorg/partiql/ast/v1/expr/WindowFunction;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/expr/WindowFunction;
 }
 
-public class org/partiql/ast/v1/graph/GraphDirection : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/graph/GraphDirection : org/partiql/ast/v1/AstEnum {
 	public static final field LEFT I
 	public static final field LEFT_OR_RIGHT I
 	public static final field LEFT_OR_UNDIRECTED I
@@ -7368,12 +7395,14 @@ public class org/partiql/ast/v1/graph/GraphDirection : org/partiql/ast/v1/Enum {
 	public static fun UNDIRECTED ()Lorg/partiql/ast/v1/graph/GraphDirection;
 	public static fun UNDIRECTED_OR_RIGHT ()Lorg/partiql/ast/v1/graph/GraphDirection;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/graph/GraphDirection;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/graph/GraphDirection;
-	public static fun values ()[Lorg/partiql/ast/v1/graph/GraphDirection;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/graph/GraphDirection;
 }
 
 public abstract class org/partiql/ast/v1/graph/GraphLabel : org/partiql/ast/v1/AstNode {
@@ -7599,7 +7628,7 @@ public class org/partiql/ast/v1/graph/GraphQuantifier$Builder {
 	public fun upper (Ljava/lang/Long;)Lorg/partiql/ast/v1/graph/GraphQuantifier$Builder;
 }
 
-public class org/partiql/ast/v1/graph/GraphRestrictor : org/partiql/ast/v1/Enum {
+public class org/partiql/ast/v1/graph/GraphRestrictor : org/partiql/ast/v1/AstEnum {
 	public static final field ACYCLIC I
 	public static final field SIMPLE I
 	public static final field TRAIL I
@@ -7608,12 +7637,14 @@ public class org/partiql/ast/v1/graph/GraphRestrictor : org/partiql/ast/v1/Enum
 	public static fun SIMPLE ()Lorg/partiql/ast/v1/graph/GraphRestrictor;
 	public static fun TRAIL ()Lorg/partiql/ast/v1/graph/GraphRestrictor;
 	public static fun UNKNOWN ()Lorg/partiql/ast/v1/graph/GraphRestrictor;
+	public fun accept (Lorg/partiql/ast/v1/AstVisitor;Ljava/lang/Object;)Ljava/lang/Object;
 	protected fun canEqual (Ljava/lang/Object;)Z
+	public fun children ()Ljava/util/Collection;
 	public fun code ()I
+	public static fun codes ()[I
 	public fun equals (Ljava/lang/Object;)Z
 	public fun hashCode ()I
-	public static fun valueOf (Ljava/lang/String;)Lorg/partiql/ast/v1/graph/GraphRestrictor;
-	public static fun values ()[Lorg/partiql/ast/v1/graph/GraphRestrictor;
+	public static fun parse (Ljava/lang/String;)Lorg/partiql/ast/v1/graph/GraphRestrictor;
 }
 
 public abstract class org/partiql/ast/v1/graph/GraphSelector : org/partiql/ast/v1/AstNode {
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/AstEnum.java b/partiql-ast/src/main/java/org/partiql/ast/v1/AstEnum.java
new file mode 100644
index 000000000..31e644a1f
--- /dev/null
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/AstEnum.java
@@ -0,0 +1,8 @@
+package org.partiql.ast.v1;
+
+/**
+ * TODO docs, equals, hashcode
+ */
+public abstract class AstEnum extends AstNode {
+    public abstract int code();
+}
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/DataType.java b/partiql-ast/src/main/java/org/partiql/ast/v1/DataType.java
index 70804ebe3..a23d7531e 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/DataType.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/DataType.java
@@ -3,8 +3,12 @@
 import lombok.EqualsAndHashCode;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
 @EqualsAndHashCode(callSuper = false)
-public class DataType implements Enum {
+public class DataType extends AstEnum {
     public static final int UNKNOWN = 0;
     // <absent types>
     public static final int NULL = 1;
@@ -396,7 +400,58 @@ public int code() {
         return code;
     }
 
-    public static DataType valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        NULL,
+        MISSING,
+        BOOL,
+        BOOLEAN,
+        TINYINT,
+        SMALLINT,
+        INTEGER2,
+        INT2,
+        INTEGER,
+        INT,
+        INTEGER4,
+        INT4,
+        INTEGER8,
+        INT8,
+        BIGINT,
+        REAL,
+        DOUBLE_PRECISION,
+        FLOAT,
+        DECIMAL,
+        DEC,
+        NUMERIC,
+        BIT,
+        BIT_VARYING,
+        CHAR,
+        CHARACTER,
+        VARCHAR,
+        CHARACTER_LARGE_OBJECT,
+        CHAR_LARGE_OBJECT,
+        CHAR_VARYING,
+        STRING,
+        SYMBOL,
+        BLOB,
+        BINARY_LARGE_OBJECT,
+        CLOB,
+        DATE,
+        STRUCT,
+        TUPLE,
+        LIST,
+        SEXP,
+        BAG,
+        TIME,
+        TIME_WITH_TIME_ZONE,
+        TIMESTAMP,
+        TIMESTAMP_WITH_TIME_ZONE,
+        INTERVAL,
+        USER_DEFINED
+    };
+
+    @NotNull
+    public static DataType parse(@NotNull String value) {
         switch (value) {
             case "NULL": return NULL();
             case "MISSING": return MISSING();
@@ -448,55 +503,9 @@ public static DataType valueOf(String value) {
         }
     }
 
-    public static DataType[] values() {
-        return new DataType[] {
-            NULL(),
-            MISSING(),
-            BOOL(),
-            BOOLEAN(),
-            TINYINT(),
-            SMALLINT(),
-            INTEGER2(),
-            INT2(),
-            INTEGER(),
-            INT(),
-            INTEGER4(),
-            INT4(),
-            INTEGER8(),
-            INT8(),
-            BIGINT(),
-            REAL(),
-            DOUBLE_PRECISION(),
-            FLOAT(),
-            DECIMAL(),
-            DEC(),
-            NUMERIC(),
-            BIT(),
-            BIT_VARYING(),
-            CHAR(),
-            CHARACTER(),
-            VARCHAR(),
-            CHARACTER_LARGE_OBJECT(),
-            CHAR_LARGE_OBJECT(),
-            CHAR_VARYING(),
-            STRING(),
-            SYMBOL(),
-            BLOB(),
-            BINARY_LARGE_OBJECT(),
-            CLOB(),
-            DATE(),
-            STRUCT(),
-            TUPLE(),
-            LIST(),
-            SEXP(),
-            BAG(),
-            TIME(),
-            TIME_WITH_TIME_ZONE(),
-            TIMESTAMP(),
-            TIMESTAMP_WITH_TIME_ZONE(),
-            INTERVAL(),
-            USER_DEFINED()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
     }
 
     /**
@@ -530,4 +539,19 @@ public Integer getLength() {
     public IdentifierChain getName() {
         return name;
     }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        List<AstNode> kids = new ArrayList<>();
+        if (name != null) {
+            kids.add(name);
+        }
+        return kids;
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
+    }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/DatetimeField.java b/partiql-ast/src/main/java/org/partiql/ast/v1/DatetimeField.java
index 2c8d42a69..b97b78355 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/DatetimeField.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/DatetimeField.java
@@ -1,12 +1,16 @@
 package org.partiql.ast.v1;
 
 import lombok.EqualsAndHashCode;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class DatetimeField implements Enum {
+public class DatetimeField extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int YEAR = 1;
     public static final int MONTH = 2;
@@ -64,7 +68,20 @@ public int code() {
         return code;
     }
 
-    public static DatetimeField valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        YEAR,
+        MONTH,
+        DAY,
+        HOUR,
+        MINUTE,
+        SECOND,
+        TIMEZONE_HOUR,
+        TIMEZONE_MINUTE
+    };
+
+    @NotNull
+    public static DatetimeField parse(@NotNull String value) {
         switch (value) {
             case "YEAR": return YEAR();
             case "MONTH": return MONTH();
@@ -78,16 +95,19 @@ public static DatetimeField valueOf(String value) {
         }
     }
 
-    public static DatetimeField[] values() {
-        return new DatetimeField[] {
-            YEAR(),
-            MONTH(),
-            DAY(),
-            HOUR(),
-            MINUTE(),
-            SECOND(),
-            TIMEZONE_HOUR(),
-            TIMEZONE_MINUTE()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/Enum.java b/partiql-ast/src/main/java/org/partiql/ast/v1/Enum.java
deleted file mode 100644
index e4551f21f..000000000
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/Enum.java
+++ /dev/null
@@ -1,8 +0,0 @@
-package org.partiql.ast.v1;
-
-/**
- * TODO docs, equals, hashcode
- */
-public interface Enum {
-    int code();
-}
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/FromType.java b/partiql-ast/src/main/java/org/partiql/ast/v1/FromType.java
index 74e0f7db9..757c8caef 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/FromType.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/FromType.java
@@ -1,12 +1,16 @@
 package org.partiql.ast.v1;
 
 import lombok.EqualsAndHashCode;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class FromType implements Enum {
+public class FromType extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int SCAN = 1;
     public static final int UNPIVOT = 2;
@@ -34,7 +38,14 @@ public int code() {
         return code;
     }
 
-    public static FromType valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        SCAN,
+        UNPIVOT
+    };
+
+    @NotNull
+    public static FromType parse(@NotNull String value) {
         switch (value) {
             case "SCAN": return SCAN();
             case "UNPIVOT": return UNPIVOT();
@@ -42,10 +53,19 @@ public static FromType valueOf(String value) {
         }
     }
 
-    public static FromType[] values() {
-        return new FromType[] {
-            SCAN(),
-            UNPIVOT()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/GroupByStrategy.java b/partiql-ast/src/main/java/org/partiql/ast/v1/GroupByStrategy.java
index a24e1316f..c39938404 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/GroupByStrategy.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/GroupByStrategy.java
@@ -1,12 +1,16 @@
 package org.partiql.ast.v1;
 
 import lombok.EqualsAndHashCode;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class GroupByStrategy implements Enum {
+public class GroupByStrategy extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int FULL = 1;
     public static final int PARTIAL = 2;
@@ -25,6 +29,12 @@ public static GroupByStrategy PARTIAL() {
 
     private final int code;
 
+    @NotNull
+    private static final int[] codes = {
+        FULL,
+        PARTIAL
+    };
+
     private GroupByStrategy(int code) {
         this.code = code;
     }
@@ -34,7 +44,8 @@ public int code() {
         return code;
     }
 
-    public static GroupByStrategy valueOf(String value) {
+    @NotNull
+    public static GroupByStrategy parse(@NotNull String value) {
         switch (value) {
             case "FULL": return FULL();
             case "PARTIAL": return PARTIAL();
@@ -42,10 +53,19 @@ public static GroupByStrategy valueOf(String value) {
         }
     }
 
-    public static GroupByStrategy[] values() {
-        return new GroupByStrategy[] {
-            FULL(),
-            PARTIAL()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/JoinType.java b/partiql-ast/src/main/java/org/partiql/ast/v1/JoinType.java
index 8a3c33e69..b77ab6aae 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/JoinType.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/JoinType.java
@@ -1,12 +1,16 @@
 package org.partiql.ast.v1;
 
 import lombok.EqualsAndHashCode;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class JoinType implements Enum {
+public class JoinType extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int INNER = 1;
     public static final int LEFT = 2;
@@ -64,7 +68,20 @@ public int code() {
         return code;
     }
 
-    public static JoinType valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        INNER,
+        LEFT,
+        LEFT_OUTER,
+        RIGHT,
+        RIGHT_OUTER,
+        FULL,
+        FULL_OUTER,
+        CROSS
+    };
+
+    @NotNull
+    public static JoinType parse(@NotNull String value) {
         switch (value) {
             case "INNER": return INNER();
             case "LEFT": return LEFT();
@@ -78,16 +95,19 @@ public static JoinType valueOf(String value) {
         }
     }
 
-    public static JoinType[] values() {
-        return new JoinType[] {
-            INNER(),
-            LEFT(),
-            LEFT_OUTER(),
-            RIGHT(),
-            RIGHT_OUTER(),
-            FULL(),
-            FULL_OUTER(),
-            CROSS()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/Nulls.java b/partiql-ast/src/main/java/org/partiql/ast/v1/Nulls.java
index b1a5c7b41..685f8a6b3 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/Nulls.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/Nulls.java
@@ -1,12 +1,16 @@
 package org.partiql.ast.v1;
 
 import lombok.EqualsAndHashCode;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class Nulls implements Enum {
+public class Nulls extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int FIRST = 1;
     public static final int LAST = 2;
@@ -34,7 +38,14 @@ public int code() {
         return code;
     }
 
-    public static Nulls valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        FIRST,
+        LAST
+    };
+
+    @NotNull
+    public static Nulls parse(@NotNull String value) {
         switch (value) {
             case "UNKNOWN": return UNKNOWN();
             case "FIRST": return FIRST();
@@ -43,10 +54,19 @@ public static Nulls valueOf(String value) {
         }
     }
 
-    public static Nulls[] values() {
-        return new Nulls[] {
-            FIRST(),
-            LAST()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/Order.java b/partiql-ast/src/main/java/org/partiql/ast/v1/Order.java
index 18f888d05..1b8874d45 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/Order.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/Order.java
@@ -1,9 +1,13 @@
 package org.partiql.ast.v1;
 
 import lombok.EqualsAndHashCode;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
 
 @EqualsAndHashCode(callSuper = false)
-public class Order implements Enum {
+public class Order extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int ASC = 1;
     public static final int DESC = 2;
@@ -31,7 +35,14 @@ public int code() {
         return code;
     }
 
-    public static Order valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        ASC,
+        DESC
+    };
+
+    @NotNull
+    public static Order parse(@NotNull String value) {
         switch (value) {
             case "ASC": return ASC();
             case "DESC": return DESC();
@@ -39,10 +50,19 @@ public static Order valueOf(String value) {
         }
     }
 
-    public static Order[] values() {
-        return new Order[] {
-            ASC(),
-            DESC()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/SetOpType.java b/partiql-ast/src/main/java/org/partiql/ast/v1/SetOpType.java
index 1a6b71f20..8be3789ec 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/SetOpType.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/SetOpType.java
@@ -1,12 +1,16 @@
 package org.partiql.ast.v1;
 
 import lombok.EqualsAndHashCode;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class SetOpType implements Enum {
+public class SetOpType extends AstEnum {
     private static final int UNKNOWN = 0;
     private static final int UNION = 1;
     private static final int INTERSECT = 2;
@@ -39,9 +43,16 @@ public int code() {
         return code;
     }
 
-    public static SetOpType valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        UNION,
+        INTERSECT,
+        EXCEPT
+    };
+
+    @NotNull
+    public static SetOpType parse(@NotNull String value) {
         switch (value) {
-            case "UNKNOWN": return UNKNOWN();
             case "UNION": return UNION();
             case "INTERSECT": return INTERSECT();
             case "EXCEPT": return EXCEPT();
@@ -49,11 +60,19 @@ public static SetOpType valueOf(String value) {
         }
     }
 
-    public static SetOpType[] values() {
-        return new SetOpType[] {
-            UNION(),
-            INTERSECT(),
-            EXCEPT()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/SetQuantifier.java b/partiql-ast/src/main/java/org/partiql/ast/v1/SetQuantifier.java
index d5902d00c..b6a56ee07 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/SetQuantifier.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/SetQuantifier.java
@@ -1,12 +1,16 @@
 package org.partiql.ast.v1;
 
 import lombok.EqualsAndHashCode;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class SetQuantifier implements Enum {
+public class SetQuantifier extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int ALL = 1;
     public static final int DISTINCT = 2;
@@ -34,7 +38,14 @@ public int code() {
         return code;
     }
 
-    public static SetQuantifier valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        ALL,
+        DISTINCT
+    };
+
+    @NotNull
+    public static SetQuantifier parse(@NotNull String value) {
         switch (value) {
             case "ALL": return ALL();
             case "DISTINCT": return DISTINCT();
@@ -42,10 +53,19 @@ public static SetQuantifier valueOf(String value) {
         }
     }
 
-    public static SetQuantifier[] values() {
-        return new SetQuantifier[] {
-            ALL(),
-            DISTINCT()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/expr/Scope.java b/partiql-ast/src/main/java/org/partiql/ast/v1/expr/Scope.java
index ea2e2abdc..ce02e250e 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/expr/Scope.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/expr/Scope.java
@@ -1,13 +1,19 @@
 package org.partiql.ast.v1.expr;
 
 import lombok.EqualsAndHashCode;
-import org.partiql.ast.v1.Enum;
+import org.jetbrains.annotations.NotNull;
+import org.partiql.ast.v1.AstEnum;
+import org.partiql.ast.v1.AstNode;
+import org.partiql.ast.v1.AstVisitor;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class Scope implements Enum {
+public class Scope extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int DEFAULT = 1;
     public static final int LOCAL = 2;
@@ -35,7 +41,14 @@ public int code() {
         return code;
     }
 
-    public static Scope valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        DEFAULT,
+        LOCAL
+    };
+
+    @NotNull
+    public static Scope parse(@NotNull String value) {
         switch (value) {
             case "UNKNOWN": return UNKNOWN();
             case "DEFAULT": return DEFAULT();
@@ -44,10 +57,19 @@ public static Scope valueOf(String value) {
         }
     }
 
-    public static Scope[] values() {
-        return new Scope[] {
-            DEFAULT(),
-            LOCAL()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/expr/SessionAttribute.java b/partiql-ast/src/main/java/org/partiql/ast/v1/expr/SessionAttribute.java
index 56a348da3..2ddde378d 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/expr/SessionAttribute.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/expr/SessionAttribute.java
@@ -1,13 +1,19 @@
 package org.partiql.ast.v1.expr;
 
 import lombok.EqualsAndHashCode;
-import org.partiql.ast.v1.Enum;
+import org.jetbrains.annotations.NotNull;
+import org.partiql.ast.v1.AstEnum;
+import org.partiql.ast.v1.AstNode;
+import org.partiql.ast.v1.AstVisitor;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class SessionAttribute implements Enum {
+public class SessionAttribute extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int CURRENT_USER = 1;
     public static final int CURRENT_DATE = 2;
@@ -35,7 +41,14 @@ public int code() {
         return code;
     }
 
-    public static SessionAttribute valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        CURRENT_USER,
+        CURRENT_DATE
+    };
+
+    @NotNull
+    public static SessionAttribute parse(@NotNull String value) {
         switch (value) {
             case "CURRENT_USER": return CURRENT_USER();
             case "CURRENT_DATE": return CURRENT_DATE();
@@ -43,10 +56,19 @@ public static SessionAttribute valueOf(String value) {
         }
     }
 
-    public static SessionAttribute[] values() {
-        return new SessionAttribute[] {
-            CURRENT_USER(),
-            CURRENT_DATE()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/expr/TrimSpec.java b/partiql-ast/src/main/java/org/partiql/ast/v1/expr/TrimSpec.java
index 00185925f..0e63de30a 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/expr/TrimSpec.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/expr/TrimSpec.java
@@ -1,10 +1,16 @@
 package org.partiql.ast.v1.expr;
 
 import lombok.EqualsAndHashCode;
-import org.partiql.ast.v1.Enum;
+import org.jetbrains.annotations.NotNull;
+import org.partiql.ast.v1.AstEnum;
+import org.partiql.ast.v1.AstNode;
+import org.partiql.ast.v1.AstVisitor;
+
+import java.util.Collection;
+import java.util.Collections;
 
 @EqualsAndHashCode(callSuper = false)
-public class TrimSpec implements Enum {
+public class TrimSpec extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int LEADING = 1;
     public static final int TRAILING = 2;
@@ -37,7 +43,15 @@ public int code() {
         return code;
     }
 
-    public static TrimSpec valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        LEADING,
+        TRAILING,
+        BOTH
+    };
+
+    @NotNull
+    public static TrimSpec parse(@NotNull String value) {
         switch (value) {
             case "LEADING": return LEADING();
             case "TRAILING": return TRAILING();
@@ -46,11 +60,19 @@ public static TrimSpec valueOf(String value) {
         }
     }
 
-    public static TrimSpec[] values() {
-        return new TrimSpec[] {
-            LEADING(),
-            TRAILING(),
-            BOTH()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/expr/WindowFunction.java b/partiql-ast/src/main/java/org/partiql/ast/v1/expr/WindowFunction.java
index c312f30c6..edb102f91 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/expr/WindowFunction.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/expr/WindowFunction.java
@@ -1,13 +1,19 @@
 package org.partiql.ast.v1.expr;
 
 import lombok.EqualsAndHashCode;
-import org.partiql.ast.v1.Enum;
+import org.jetbrains.annotations.NotNull;
+import org.partiql.ast.v1.AstEnum;
+import org.partiql.ast.v1.AstNode;
+import org.partiql.ast.v1.AstVisitor;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class WindowFunction implements Enum {
+public class WindowFunction extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int LAG = 0;
     public static final int LEAD = 0;
@@ -35,7 +41,14 @@ public int code() {
         return code;
     }
 
-    public static WindowFunction valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        LAG,
+        LEAD
+    };
+
+    @NotNull
+    public static WindowFunction parse(@NotNull String value) {
         switch (value) {
             case "LAG": return LAG();
             case "LEAD": return LEAD();
@@ -43,10 +56,19 @@ public static WindowFunction valueOf(String value) {
         }
     }
 
-    public static WindowFunction[] values() {
-        return new WindowFunction[] {
-            LAG(),
-            LEAD()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/graph/GraphDirection.java b/partiql-ast/src/main/java/org/partiql/ast/v1/graph/GraphDirection.java
index db8ff4b68..ddf01bfe5 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/graph/GraphDirection.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/graph/GraphDirection.java
@@ -1,13 +1,19 @@
 package org.partiql.ast.v1.graph;
 
 import lombok.EqualsAndHashCode;
-import org.partiql.ast.v1.Enum;
+import org.jetbrains.annotations.NotNull;
+import org.partiql.ast.v1.AstEnum;
+import org.partiql.ast.v1.AstNode;
+import org.partiql.ast.v1.AstVisitor;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class GraphDirection implements Enum {
+public class GraphDirection extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int LEFT = 1;
     public static final int UNDIRECTED = 2;
@@ -51,6 +57,17 @@ public static GraphDirection LEFT_UNDIRECTED_OR_RIGHT() {
 
     private final int code;
 
+    @NotNull
+    private static final int[] codes = {
+        LEFT,
+        UNDIRECTED,
+        RIGHT,
+        LEFT_OR_UNDIRECTED,
+        UNDIRECTED_OR_RIGHT,
+        LEFT_OR_RIGHT,
+        LEFT_UNDIRECTED_OR_RIGHT
+    };
+
     private GraphDirection(int code) {
         this.code = code;
     }
@@ -60,7 +77,8 @@ public int code() {
         return code;
     }
 
-    public static GraphDirection valueOf(String value) {
+    @NotNull
+    public static GraphDirection parse(@NotNull String value) {
         switch (value) {
             case "LEFT": return LEFT();
             case "UNDIRECTED": return UNDIRECTED();
@@ -73,15 +91,19 @@ public static GraphDirection valueOf(String value) {
         }
     }
 
-    public static GraphDirection[] values() {
-        return new GraphDirection[] {
-            LEFT(),
-            UNDIRECTED(),
-            RIGHT(),
-            LEFT_OR_UNDIRECTED(),
-            UNDIRECTED_OR_RIGHT(),
-            LEFT_OR_RIGHT(),
-            LEFT_UNDIRECTED_OR_RIGHT()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }
diff --git a/partiql-ast/src/main/java/org/partiql/ast/v1/graph/GraphRestrictor.java b/partiql-ast/src/main/java/org/partiql/ast/v1/graph/GraphRestrictor.java
index c73e939b1..5b491ef56 100644
--- a/partiql-ast/src/main/java/org/partiql/ast/v1/graph/GraphRestrictor.java
+++ b/partiql-ast/src/main/java/org/partiql/ast/v1/graph/GraphRestrictor.java
@@ -1,13 +1,19 @@
 package org.partiql.ast.v1.graph;
 
 import lombok.EqualsAndHashCode;
-import org.partiql.ast.v1.Enum;
+import org.jetbrains.annotations.NotNull;
+import org.partiql.ast.v1.AstEnum;
+import org.partiql.ast.v1.AstNode;
+import org.partiql.ast.v1.AstVisitor;
+
+import java.util.Collection;
+import java.util.Collections;
 
 /**
  * TODO docs, equals, hashcode
  */
 @EqualsAndHashCode(callSuper = false)
-public class GraphRestrictor implements Enum {
+public class GraphRestrictor extends AstEnum {
     public static final int UNKNOWN = 0;
     public static final int TRAIL = 1;
     public static final int ACYCLIC = 2;
@@ -40,7 +46,15 @@ public int code() {
         return code;
     }
 
-    public static GraphRestrictor valueOf(String value) {
+    @NotNull
+    private static final int[] codes = {
+        TRAIL,
+        ACYCLIC,
+        SIMPLE
+    };
+
+    @NotNull
+    public static GraphRestrictor parse(@NotNull String value) {
         switch (value) {
             case "TRAIL": return TRAIL();
             case "ACYCLIC": return ACYCLIC();
@@ -49,11 +63,19 @@ public static GraphRestrictor valueOf(String value) {
         }
     }
 
-    public static GraphRestrictor[] values() {
-        return new GraphRestrictor[] {
-            TRAIL(),
-            ACYCLIC(),
-            SIMPLE()
-        };
+    @NotNull
+    public static int[] codes() {
+        return codes;
+    }
+
+    @NotNull
+    @Override
+    public Collection<AstNode> children() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public <R, C> R accept(@NotNull AstVisitor<R, C> visitor, C ctx) {
+        return null;
     }
 }