feat: add support for link statements within namespace blocks in class diagrams

Resolves #4700

packages/mermaid/src/diagrams/class/classDiagram.spec.ts

@@ -88,6 +88,50 @@ describe('given a basic class diagram, ', function () {
       expect(relations[0].title).toBe('generates');
     });
 
+    it('should handle link statements within namespaces', function () {
+      spyOn(classDb, 'setLink');
+      const str = `classDiagram
+        namespace MyNamespace {
+          class UserService {
+            +createUser()
+            +deleteUser()
+          }
+          
+          class PaymentService {
+            +processPayment()
+            +refund()
+          }
+          
+          link UserService "https://example.com/user-service"
+          link PaymentService "https://example.com/payment-service" "Payment Service Documentation"
+        }`;
+
+      parser.parse(str);
+
+      // Verify setLink was called for both classes
+      expect(classDb.setLink).toHaveBeenCalledWith(
+        'UserService',
+        'https://example.com/user-service'
+      );
+      expect(classDb.setLink).toHaveBeenCalledWith(
+        'PaymentService',
+        'https://example.com/payment-service'
+      );
+
+      // Verify the classes have the correct links and are in the namespace
+      const userService = classDb.getClass('UserService');
+      const paymentService = classDb.getClass('PaymentService');
+
+      expect(userService.parent).toBe('MyNamespace');
+      expect(userService.link).toBe('https://example.com/user-service');
+      expect(userService.cssClasses).toBe('default clickable');
+
+      expect(paymentService.parent).toBe('MyNamespace');
+      expect(paymentService.link).toBe('https://example.com/payment-service');
+      expect(paymentService.tooltip).toBe('Payment Service Documentation');
+      expect(paymentService.cssClasses).toBe('default clickable');
+    });
+
     it('should handle accTitle and accDescr', function () {
       const str = `classDiagram
             accTitle: My Title

packages/mermaid/src/diagrams/class/parser/classDiagram.jison

@@ -275,14 +275,25 @@ statement
     ;
 
 namespaceStatement
-    : namespaceIdentifier STRUCT_START classStatements STRUCT_STOP          { yy.addClassesToNamespace($1, $3); }
-    | namespaceIdentifier STRUCT_START NEWLINE classStatements STRUCT_STOP  { yy.addClassesToNamespace($1, $4); }
+    : namespaceIdentifier STRUCT_START namespaceBodyStatements STRUCT_STOP          { yy.addClassesToNamespace($1, $3); }
+    | namespaceIdentifier STRUCT_START NEWLINE namespaceBodyStatements STRUCT_STOP  { yy.addClassesToNamespace($1, $4); }
     ;
 
 namespaceIdentifier
     : NAMESPACE namespaceName { $$=$2; yy.addNamespace($2); }
     ;
 
+namespaceBodyStatements
+    : namespaceBodyStatement                                        { $$=[$1].filter(s => s !== null); }
+    | namespaceBodyStatement NEWLINE                                { $$=[$1].filter(s => s !== null); }
+    | namespaceBodyStatement NEWLINE namespaceBodyStatements        { var filtered = [$1].filter(s => s !== null); $3.unshift(...filtered); $$=$3; }
+    ;
+
+namespaceBodyStatement
+    : classStatement                { $$=$1; }
+    | clickStatement               { $$=null; /* clickStatements don't return class names, but are processed for side effects */ }
+    ;
+
 classStatements
     : classStatement                            {$$=[$1]}
     | classStatement NEWLINE                    {$$=[$1]}

packages/mermaid/src/docs/syntax/classDiagram.md

@@ -452,6 +452,7 @@ classDiagram
 It is possible to bind a click event to a node. The click can lead to either a javascript callback or to a link which will be opened in a new browser tab. **Note**: This functionality is disabled when using `securityLevel='strict'` and enabled when using `securityLevel='loose'`.
 
 You would define these actions on a separate line after all classes have been declared.
+If you have classes defined within a namespace, you can also add interaction definitions within the namespace definition, after the class(es) is defined
 
 ```
 action className "reference" "tooltip"