Issue #26: Enhance Access '^' power operator translation to SQL POWER()

Extends operator translation to include support for parameter markers ('?').
This ensures correct translation of SQL queries used with PreparedStatements.

Updated the POWER_OPERAND_REGEX to recognize '?' and added corresponding unit tests.

Author: spannm

src/main/java/net/ucanaccess/converters/SQLConverter.java

@@ -61,10 +61,12 @@ public static final class Patterns {
         private static final String        POWER_OPERAND_REGEX        =
                 "(?:"
               + "\\b[a-zA-Z_][a-zA-Z0-9_.]*\\b" // column name/identifier
-              + "|"
+              + '|'
               + "[+-]?\\d+(?:\\.\\d*)?(?:e[+-]?\\d+)?" // numeric term
-              + "|"
+              + '|'
               + "\\([^()]+?\\)" // simple parenthesized expressions WITHOUT nested parentheses
+              + '|'
+              + "\\?" // parameter marker for PreparedStatements
               + ")";
 
         // the main pattern to find "operand1 ^ operand2"
@@ -549,13 +551,14 @@ private static String replaceWhiteSpacedTableNames0(String sql) {
      * <p>
      * This is a simplified implementation based on regular expressions and might not
      * cover all edge cases or complex SQL constructs. For robust parsing and
-     * modification of SQL, we should  use a dedicated SQL parser library e.g. JSqlParser.
+     * modification of SQL, we should use a dedicated SQL parser library e.g. JSqlParser.
      *
      * <p>The current implementation's {@code POWER_OPERAND_REGEX} is designed to identify:</p>
      * <ul>
      *   <li>Simple column names or identifiers (e.g., {@code myColumn}, {@code Table.Column}).</li>
      *   <li>Numeric literals (integers, decimals, scientific notation, with optional sign).</li>
      *   <li>Simple parenthesized expressions without nested parentheses (e.g., {@code (num + 1)}).</li>
+     *   <li>Parameter markers ({@code ?}) for use in {@code PreparedStatement} scenarios.</li>
      * </ul>
      * <p>It explicitly **does NOT reliably handle** operands that are:</p>
      * <ul>

src/test/java/net/ucanaccess/converters/SQLConverterTest.java

@@ -68,6 +68,14 @@ private static Stream<Arguments> provideSqlTranslationData() {
                 // Edge cases: Subqueries (NOT supported by regex for operands) - should remain unchanged
                 //arguments("SELECT (SELECT X FROM Y)^2 FROM T", "SELECT (SELECT X FROM Y)^2 FROM T", "Subquery (base) - not handled"),
 
+                // parameter markers (?) for use in PreparedStatement
+                arguments("SELECT num^? FROM t", "SELECT POWER(num, ?) FROM t", "parameter marker 1a"),
+                arguments("SELECT num ^ ? FROM t", "SELECT POWER(num, ?) FROM t", "parameter marker 1b"),
+                arguments("SELECT ?^num FROM t", "SELECT POWER(?, num) FROM t", "parameter marker 2a"),
+                arguments("SELECT ? ^ num FROM t", "SELECT POWER(?, num) FROM t", "parameter marker 2b"),
+                arguments("SELECT ?^? FROM t", "SELECT POWER(?, ?) FROM t", "parameter marker 3a"),
+                arguments("SELECT ?  ^  ? FROM t", "SELECT POWER(?, ?) FROM t", "parameter marker 3b"),
+
                 // Test with empty string or null input
                 arguments(null, null, "Null input"),
                 arguments("", "", "Empty string input"),