XS: INTERFACE: support perl package names

XS currently allows a Perl package name to be used where a C type is
expected; behind the scenes, s/:/_/g is performed on the type string.

For example this XS declaration,

    X::Y
    foo(...)

causes this C declaration to be emitted for RETVAL:

    X__Y RETVAL;

However, in the presence of the INTERFACE keyword, e.g.

    X::Y
    foo(...)
      INTERFACE: ....

an extra variable to hold a function pointer is declared and
initialised, but the return type of the function gets declared as X::Y
rather than X__Y, resulting in uncompilable C code being generated.

This commit fixes that.

Before, the code emitted was:

    dXSFUNCTION(X::Y);
    XSFUNCTION = XSINTERFACE_FUNC(X::Y,cv,XSANY.any_dptr);

but is now:

    dXSFUNCTION(X__Y);
    XSFUNCTION = XSINTERFACE_FUNC(X__Y,cv,XSANY.any_dptr);

Author: iabyn

dist/ExtUtils-ParseXS/lib/ExtUtils/ParseXS/Node.pm

@@ -593,9 +593,14 @@ EOF
         |    dXSI32;
 EOF
 
-    print ExtUtils::ParseXS::Q(<<"EOF") if $self->{seen_INTERFACE};
-        |    dXSFUNCTION($self->{decl}{return_type}{type});
+    if ($self->{seen_INTERFACE}) {
+        my $type = $self->{decl}{return_type}{type};
+        $type =~ tr/:/_/
+            unless $pxs->{config_RetainCplusplusHierarchicalTypes};
+        print ExtUtils::ParseXS::Q(<<"EOF") if $self->{seen_INTERFACE};
+            |    dXSFUNCTION($type);
 EOF
+    }
 
 
     {
@@ -3724,8 +3729,11 @@ sub as_code {
     my $macro = $xsub->{interface_macro};
     $macro = 'XSINTERFACE_FUNC' unless defined $macro;
 
+    my $type = $xsub->{decl}{return_type}{type};
+    $type =~ tr/:/_/
+        unless $pxs->{config_RetainCplusplusHierarchicalTypes};
     print <<"EOF";
-    XSFUNCTION = $macro($xsub->{decl}{return_type}{type},cv,XSANY.any_dptr);
+    XSFUNCTION = $macro($type,cv,XSANY.any_dptr);
 EOF
 }
 

dist/ExtUtils-ParseXS/t/001-basic.t

@@ -4828,6 +4828,24 @@ EOF
             [ 0, 0, qr{\bXSFUNCTION\(\)},
                    "got XSFUNCTION call" ],
         ],
+        [
+            'INTERFACE with perl package name',
+            [ Q(<<'EOF') ],
+                |TYPEMAP: <<EOTM
+                |X::Y T_IV
+                |EOTM
+                |
+                |X::Y
+                |foo()
+                |    INTERFACE: f1
+EOF
+            [ 0, 0, qr{\b\QdXSFUNCTION(X__Y)},
+                   "got XSFUNCTION declaration" ],
+            [ 0, 0, qr{\QXSFUNCTION = XSINTERFACE_FUNC(X__Y,cv,XSANY.any_dptr);},
+                   "got XSFUNCTION assign" ],
+            [ 0, 0, qr{\bXSFUNCTION\(\)},
+                   "got XSFUNCTION call" ],
+        ],
     );
 
     test_many($preamble, 'XS_Foo_', \@test_fns);