fix: parse PostgreSQL DROP CAST, DROP OPERATOR and DROP TRANSFORM

src/main/java/net/sf/jsqlparser/statement/CastSignature.java

@@ -0,0 +1,69 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2026 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.statement;
+
+import net.sf.jsqlparser.parser.ASTNodeAccessImpl;
+import net.sf.jsqlparser.statement.create.table.ColDataType;
+
+/**
+ * A PostgreSQL cast, named by the types it converts between: {@code (source_type AS target_type)},
+ * as in {@code DROP CAST (text AS integer)}.
+ */
+public class CastSignature extends ASTNodeAccessImpl {
+
+    private ColDataType sourceType;
+    private ColDataType targetType;
+
+    public CastSignature() {
+        // the types are set by the parser or the setters
+    }
+
+    public CastSignature(ColDataType sourceType, ColDataType targetType) {
+        this.sourceType = sourceType;
+        this.targetType = targetType;
+    }
+
+    public ColDataType getSourceType() {
+        return sourceType;
+    }
+
+    public void setSourceType(ColDataType sourceType) {
+        this.sourceType = sourceType;
+    }
+
+    public CastSignature withSourceType(ColDataType sourceType) {
+        setSourceType(sourceType);
+        return this;
+    }
+
+    public ColDataType getTargetType() {
+        return targetType;
+    }
+
+    public void setTargetType(ColDataType targetType) {
+        this.targetType = targetType;
+    }
+
+    public CastSignature withTargetType(ColDataType targetType) {
+        setTargetType(targetType);
+        return this;
+    }
+
+    @Override
+    public StringBuilder appendTo(StringBuilder builder) {
+        return builder.append('(').append(sourceType).append(" AS ").append(targetType)
+                .append(')');
+    }
+
+    @Override
+    public String toString() {
+        return appendTo(new StringBuilder()).toString();
+    }
+}

src/main/java/net/sf/jsqlparser/statement/OperatorSignature.java

@@ -0,0 +1,95 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2026 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.statement;
+
+import net.sf.jsqlparser.parser.ASTNodeAccessImpl;
+import net.sf.jsqlparser.statement.create.table.ColDataType;
+import net.sf.jsqlparser.statement.create.table.ExclusionOperator;
+
+/**
+ * A PostgreSQL operator, named by its possibly schema-qualified symbol and its operand types:
+ * {@code [schema.]op ({left_type | NONE}, {right_type | NONE})}, as in
+ * {@code DROP OPERATOR ~ (NONE, bigint)}. A null operand type is the NONE marker of a missing
+ * operand, and is rendered as {@code NONE}.
+ */
+public class OperatorSignature extends ASTNodeAccessImpl {
+
+    private ExclusionOperator operator;
+    private ColDataType leftType;
+    private ColDataType rightType;
+
+    public OperatorSignature() {
+        // the operator and its operand types are set by the parser or the setters
+    }
+
+    public OperatorSignature(ExclusionOperator operator, ColDataType leftType,
+            ColDataType rightType) {
+        this.operator = operator;
+        this.leftType = leftType;
+        this.rightType = rightType;
+    }
+
+    /** The operator symbol and its schema, read by the reference COMMENT ON OPERATOR uses. */
+    public ExclusionOperator getOperator() {
+        return operator;
+    }
+
+    public void setOperator(ExclusionOperator operator) {
+        this.operator = operator;
+    }
+
+    public OperatorSignature withOperator(ExclusionOperator operator) {
+        setOperator(operator);
+        return this;
+    }
+
+    /** The left operand type, or null for NONE, the missing left operand of a prefix operator. */
+    public ColDataType getLeftType() {
+        return leftType;
+    }
+
+    public void setLeftType(ColDataType leftType) {
+        this.leftType = leftType;
+    }
+
+    public OperatorSignature withLeftType(ColDataType leftType) {
+        setLeftType(leftType);
+        return this;
+    }
+
+    /** The right operand type, or null for NONE. */
+    public ColDataType getRightType() {
+        return rightType;
+    }
+
+    public void setRightType(ColDataType rightType) {
+        this.rightType = rightType;
+    }
+
+    public OperatorSignature withRightType(ColDataType rightType) {
+        setRightType(rightType);
+        return this;
+    }
+
+    @Override
+    public StringBuilder appendTo(StringBuilder builder) {
+        return builder.append(operator).append(" (").append(operand(leftType)).append(", ")
+                .append(operand(rightType)).append(')');
+    }
+
+    private static Object operand(ColDataType type) {
+        return type == null ? "NONE" : type;
+    }
+
+    @Override
+    public String toString() {
+        return appendTo(new StringBuilder()).toString();
+    }
+}

src/main/java/net/sf/jsqlparser/statement/TransformSignature.java

@@ -0,0 +1,69 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2026 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.statement;
+
+import net.sf.jsqlparser.parser.ASTNodeAccessImpl;
+import net.sf.jsqlparser.statement.create.table.ColDataType;
+
+/**
+ * A PostgreSQL transform, named by the data type and the procedural language it connects:
+ * {@code FOR type_name LANGUAGE lang_name}, as in
+ * {@code DROP TRANSFORM FOR hstore LANGUAGE plpython3u}.
+ */
+public class TransformSignature extends ASTNodeAccessImpl {
+
+    private ColDataType dataType;
+    private String language;
+
+    public TransformSignature() {
+        // the type and language are set by the parser or the setters
+    }
+
+    public TransformSignature(ColDataType dataType, String language) {
+        this.dataType = dataType;
+        this.language = language;
+    }
+
+    public ColDataType getDataType() {
+        return dataType;
+    }
+
+    public void setDataType(ColDataType dataType) {
+        this.dataType = dataType;
+    }
+
+    public TransformSignature withDataType(ColDataType dataType) {
+        setDataType(dataType);
+        return this;
+    }
+
+    public String getLanguage() {
+        return language;
+    }
+
+    public void setLanguage(String language) {
+        this.language = language;
+    }
+
+    public TransformSignature withLanguage(String language) {
+        setLanguage(language);
+        return this;
+    }
+
+    @Override
+    public StringBuilder appendTo(StringBuilder builder) {
+        return builder.append("FOR ").append(dataType).append(" LANGUAGE ").append(language);
+    }
+
+    @Override
+    public String toString() {
+        return appendTo(new StringBuilder()).toString();
+    }
+}

src/main/java/net/sf/jsqlparser/statement/create/table/ExclusionOperator.java

@@ -13,7 +13,7 @@
 
 /**
  * An exclusion operator, optionally qualified and enclosed in PostgreSQL OPERATOR(...). COMMENT ON
- * OPERATOR uses the same reference without the OPERATOR keyword.
+ * OPERATOR and DROP OPERATOR use the same reference without the OPERATOR keyword.
  */
 public class ExclusionOperator implements Serializable {
     private String schemaName;