Add $isvoid special variable expansion for directors

Complete the removal of Ruby's output_helper macro and replacement
with SWIG_AppendOutput for director typemaps.
Requires $isvoid special variable support in director code.

CHANGES.current

@@ -10,7 +10,9 @@ Version 4.3.0 (in progress)
 2024-10-05: wsfulton
             [Ruby] Removed backwards compatible output_helper fragment and macro.
             Use SWIG_AppendOutput instead of output_helper (does not require the
-            output_helper macro).
+            output_helper fragment).
+
+	    *** POTENTIAL INCOMPATIBILITY ***
 
 2024-10-05: wsfulton
             [Ruby] #2907 Fix returning null from functions with output parameters.
@@ -315,6 +317,8 @@ Version 4.3.0 (in progress)
             [Python] Removed deprecated pytuplehlp.swg file and t_output_helper.
             Use SWIG_Python_AppendOutput instead of t_output_helper.
 
+	    *** POTENTIAL INCOMPATIBILITY ***
+
 2024-06-15: vadz
             [Python] #2907 Fix returning null from functions with output parameters.
             Ensures OUTPUT and INOUT typemaps are handled consistently wrt return

Doc/Manual/Ruby.html

@@ -2885,9 +2885,9 @@ example:</p>
   $1 = &amp;temp;
 }
 
-%typemap(argout, fragment="output_helper") int *out {
+%typemap(argout) int *out {
   // Append output value $1 to $result (assuming a single integer in this case)
-  $result = output_helper( $result, INT2NUM(*$1) );
+  $result = SWIG_AppendOutput( $result, INT2NUM(*$1) );
 }</pre>
 </div>
 
@@ -3187,9 +3187,8 @@ exception.
 member functions.</p>
 
 <div class="code"><pre>
-%typemap(directorargout,
-fragment="output_helper") int {
-  $result = output_helper( $result, NUM2INT($1) );
+%typemap(directorargout) int {
+  $result = SWIG_AppendOutput( $result, NUM2INT($1) );
 }
 </pre></div>
 

Examples/test-suite/special_variables.i

@@ -127,6 +127,7 @@ void DirectorTest_director_testmethodSwigExplicitDirectorTest(int i) {}
 %}
 %typemap(directorargout) int i {
   $symname(99);
+  int isvoid_special_variable = $isvoid;
 }
 %feature("director") DirectorTest;
 %inline %{

Source/Modules/csharp.cxx

@@ -4440,6 +4440,7 @@ public:
       } else {
 	Replaceall(w->code, "$null", "");
       }
+      Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
       if (!ignored_method)
 	Printv(director_delegate_callback, "\n", callback_def, callback_code, NIL);
       if (!Getattr(n, "defaultargs")) {

Source/Modules/d.cxx

@@ -2347,6 +2347,7 @@ public:
       } else {
 	Replaceall(w->code, "$null", "");
       }
+      Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
       if (!ignored_method)
 	Printv(director_dcallbacks_code, callback_def, callback_code, NIL);
       if (!Getattr(n, "defaultargs")) {

Source/Modules/go.cxx

@@ -3264,7 +3264,9 @@ private:
     Swig_typemap_attach_parms("imtype", parms, NULL);
     int parm_count = emit_num_arguments(parms);
 
-    SwigType *result = Getattr(n, "type");
+    SwigType *returntype = Getattr(n, "type");
+    SwigType *result = returntype;
+    bool is_void = !(Cmp(returntype, "void"));
 
     // Save the type for overload processing.
     Setattr(n, "go:type", result);
@@ -3998,6 +4000,7 @@ private:
 
       Printv(w->code, "}", NULL);
 
+      Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
       Replaceall(w->code, "$symname", symname);
       Wrapper_print(w, f_c_directors);
     }

Source/Modules/java.cxx

@@ -4518,6 +4518,7 @@ public:
       } else {
 	Replaceall(w->code, "$null", "");
       }
+      Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
       if (!GetFlag(n, "feature:ignore"))
 	Printv(imclass_directors, callback_def, callback_code, NIL);
       if (!Getattr(n, "defaultargs")) {

Source/Modules/ocaml.cxx

@@ -1669,6 +1669,7 @@ public:
 
     /* emit the director method */
     if (status == SWIG_OK) {
+      Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
       if (!Getattr(n, "defaultargs")) {
 	Replaceall(w->code, "$symname", symname);
 	Wrapper_print(w, f_directors);

Source/Modules/octave.cxx

@@ -1538,6 +1538,7 @@ public:
     }
     // emit the director method
     if (status == SWIG_OK) {
+      Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
       if (!Getattr(n, "defaultargs")) {
         Replaceall(w->code, "$symname", symname);
         Wrapper_print(w, f_directors);

Source/Modules/perl5.cxx

@@ -2442,6 +2442,7 @@ public:
 
     /* emit the director method */
     if (status == SWIG_OK) {
+      Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
       if (!Getattr(n, "defaultargs")) {
 	Replaceall(w->code, "$symname", symname);
 	Wrapper_print(w, f_directors);
@@ -2456,6 +2457,7 @@ public:
     DelWrapper(w);
     return status;
   }
+
   int classDirectorDisown(Node *n) {
     int rv;
     member_func = 1;
@@ -2468,6 +2470,7 @@ public:
     }
     return rv;
   }
+
   int classDirectorDestructor(Node *n) {
     /* TODO: it would be nice if this didn't have to copy the body of Language::classDirectorDestructor() */
     String *DirectorClassName = directorClassName(getCurrentClass());

Source/Modules/php.cxx

@@ -2517,6 +2517,7 @@ public:
 
     /* emit the director method */
     if (status == SWIG_OK) {
+      Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
       if (!Getattr(n, "defaultargs")) {
 	Replaceall(w->code, "$symname", symname);
 	Wrapper_print(w, f_directors);

Source/Modules/python.cxx

@@ -5891,6 +5891,7 @@ int PYTHON::classDirectorMethod(Node *n, Node *parent, String *super) {
 
   /* emit the director method */
   if (status == SWIG_OK) {
+    Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
     if (!Getattr(n, "defaultargs")) {
       Replaceall(w->code, "$symname", symname);
       Wrapper_print(w, f_directors);

Source/Modules/ruby.cxx

@@ -3366,6 +3366,7 @@ public:
 
     /* emit the director method */
     if (status == SWIG_OK) {
+      Replaceall(w->code, "$isvoid", is_void ? "1" : "0");
       if (!Getattr(n, "defaultargs")) {
 	Replaceall(w->code, "$symname", symname);
 	Wrapper_print(w, f_directors);