Add support for friend templates, including operator overloading.

Closes swig#196.

CHANGES.current

@@ -5,6 +5,27 @@ See the RELEASENOTES file for a summary of changes in each release.
 Version 3.0.6 (in progress)
 ===========================
 
+2015-05-04: wsfulton
+            Add support for friend templates, including operator overloading - fixes #196. Considering
+            the example below, previously the operator gave a syntax error and friendfunc incorrectly
+            warned with:
+
+             "Warning 503: Can't wrap 'friendfunc<(Type)>' unless renamed to a valid identifier."
+
+              template <class Type> class MyClass {
+                friend int friendfunc <Type>(double is, MyClass <Type> & x);
+                friend int operator<< <Type>(double un, const MyClass <Type> &x);
+              };
+
+            The following also previously incorrectly warned with:
+
+              "Warning 302: Identifier 'template_friend' redefined (ignored),"
+
+              template<typename T> T template_friend(T);
+              struct MyTemplate {
+                template<typename T> friend T template_friend(T);
+              };
+
 2015-05-01: wsfulton
             Fix handling of conversion operators where the operator is split over multiple
             lines or has comments within the operator type. Fixes #401.

Examples/test-suite/common.mk

@@ -234,6 +234,7 @@ CPP_TEST_CASES += \
 	features \
 	fragments \
 	friends \
+	friends_template \
 	funcptr_cpp \
 	fvirtual \
 	global_namespace \

Examples/test-suite/errors/cpp_template_friend.i

@@ -0,0 +1,26 @@
+%module cpp_template_friend
+
+template<typename T> T template_friend1(T);
+template<typename T> T template_friend1(T);
+struct MyTemplate1 {
+  template<typename T> friend T template_friend1(T);
+};
+
+template<typename T> T template_friend2(T);
+struct MyTemplate2 {
+  template<typename T> friend T template_friend2(T);
+};
+template<typename T> T template_friend2(T);
+
+
+int normal_friend1(int);
+int normal_friend1(int);
+struct MyClass1 {
+  friend int normal_friend1(int);
+};
+
+int normal_friend2(int);
+struct MyClass2 {
+  friend int normal_friend2(int);
+};
+int normal_friend2(int);

Examples/test-suite/errors/cpp_template_friend.stderr

@@ -0,0 +1,8 @@
+cpp_template_friend.i:4: Warning 302: Identifier 'template_friend1' redefined (ignored),
+cpp_template_friend.i:3: Warning 302: previous definition of 'template_friend1'.
+cpp_template_friend.i:13: Warning 302: Identifier 'template_friend2' redefined (ignored),
+cpp_template_friend.i:9: Warning 302: previous definition of 'template_friend2'.
+cpp_template_friend.i:17: Warning 322: Redundant redeclaration of 'normal_friend1',
+cpp_template_friend.i:16: Warning 322: previous declaration of 'normal_friend1'.
+cpp_template_friend.i:26: Warning 322: Redundant redeclaration of 'normal_friend2',
+cpp_template_friend.i:22: Warning 322: previous declaration of 'normal_friend2'.

Examples/test-suite/friends_template.i

@@ -0,0 +1,46 @@
+%module friends_template
+
+%{
+template <typename Type> class MyClass;
+
+template <typename Type> int operator<<(double un, const MyClass <Type> & x) { return 0; }
+template <typename Type> int funk_hidden(double is, MyClass <Type>  & x) { return 2; }
+
+template <typename T> T template_friend_hidden(T t) { return t + 1; }
+%}
+
+%inline %{
+template <typename Type> int operator>>(double is, MyClass <Type>  & x) { return 1; }
+template <typename Type> int funk_seen(double is, MyClass <Type>  & x) { return 2; }
+template <typename T> T template_friend_seen(T t1, T t2) { return t1 + t2; }
+int friend_plain_seen(int i) { return i; }
+
+template <class Type> class MyClass
+{
+  friend int operator<<  <Type>(double un, const MyClass <Type> & x);
+  friend int operator>>  <Type>(double is, MyClass <Type> & x);
+  friend int funk_hidden <Type>(double is, MyClass <Type> & x);
+  friend int funk_seen   <Type>(double is, MyClass <Type> & x);
+};
+
+struct MyTemplate {
+  template <typename T> friend T template_friend_hidden(T);
+  template <typename T> friend T template_friend_seen(T, T);
+  friend int friend_plain_seen(int i);
+};
+
+MyClass<int> makeMyClassInt() { return MyClass<int>(); }
+%}
+
+// Although the friends in MyClass are automatically instantiated via %template(MyClassDouble) MyClass<int>,
+// the operator friends are not valid and hence %rename is needed.
+%rename(OperatorInputDouble) operator>> <double>;
+%rename(OperatorOutputDouble) operator<< <double>;
+%template(MyClassDouble) MyClass<double>;
+
+%template(TemplateFriendHiddenInt) template_friend_hidden<int>;
+%template(TemplateFriendSeenInt) template_friend_seen<int>;
+
+// These have no %template(XX) MyClass<int> to instantiate, but they can be instantiated separately...
+%template(OperatorInputInt) operator>> <int>;
+%template(OperatorFunkSeenInt) funk_seen <int>;

Examples/test-suite/java/friends_template_runme.java

@@ -0,0 +1,28 @@
+
+import friends_template.*;
+
+public class friends_template_runme {
+
+  static {
+    try {
+	System.loadLibrary("friends_template");
+    } catch (UnsatisfiedLinkError e) {
+      System.err.println("Native code library failed to load. See the chapter on Dynamic Linking Problems in the SWIG Java documentation for help.\n" + e);
+      System.exit(1);
+    }
+  }
+
+  public static void main(String argv[]) {
+    friends_template.OperatorOutputDouble(1.1, new MyClassDouble());
+    friends_template.OperatorInputDouble(1.1, new MyClassDouble());
+    friends_template.funk_hidden(1.1, new MyClassDouble());
+    friends_template.funk_seen(1.1, new MyClassDouble());
+
+    friends_template.TemplateFriendHiddenInt(0);
+    friends_template.TemplateFriendSeenInt(0, 0);
+
+    SWIGTYPE_p_MyClassT_int_t myClassInt = friends_template.makeMyClassInt();
+    friends_template.OperatorInputInt(1, myClassInt);
+    friends_template.OperatorFunkSeenInt(1.1, myClassInt);
+  }
+}

Source/CParse/parser.y

@@ -6453,8 +6453,8 @@ idcolon        : idtemplate idcolontail {
                | NONID DCOLON idtemplate {
 		 $$ = NewStringf("::%s",$3);
                }
-               | OPERATOR {
-                 $$ = NewString($1);
+               | OPERATOR template_decl {
+                 $$ = NewStringf("%s%s",$1,$2);
 	       }
                | NONID DCOLON OPERATOR {
                  $$ = NewStringf("::%s",$3);

Source/CParse/templ.c

@@ -97,6 +97,15 @@ static int cparse_template_expand(Node *n, String *tname, String *rname, String
 	Append(cpatchlist, Getattr(n, "sym:name"));
       }
     }
+    if (checkAttribute(n, "storage", "friend")) {
+      String *symname = Getattr(n, "sym:name");
+      if (symname) {
+	String *stripped_name = SwigType_templateprefix(symname);
+	Setattr(n, "sym:name", stripped_name);
+	Delete(stripped_name);
+      }
+      Append(typelist, Getattr(n, "name"));
+    }
 
     add_parms(Getattr(n, "parms"), cpatchlist, typelist);
     add_parms(Getattr(n, "throws"), cpatchlist, typelist);

Source/Modules/lang.cxx

@@ -940,7 +940,7 @@ int Language::cDeclaration(Node *n) {
   }
 
   if (!validIdentifier(symname)) {
-    Swig_warning(WARN_LANG_IDENTIFIER, input_file, line_number, "Can't wrap '%s' unless renamed to a valid identifier.\n", symname);
+    Swig_warning(WARN_LANG_IDENTIFIER, input_file, line_number, "Can't wrap '%s' unless renamed to a valid identifier.\n", SwigType_namestr(symname));
     return SWIG_NOWRAP;
   }
 

Source/Swig/naming.c

@@ -1003,6 +1003,10 @@ static int nodes_are_equivalent(Node *a, Node *b, int a_inclass) {
       }
       return 0;
     }
+    if (Equal(ta, "template") && Equal(tb, "template")) {
+      if (Cmp(a_storage, "friend") == 0 || Cmp(b_storage, "friend") == 0)
+	return 1;
+    }
   }
   return 0;
 }