1 files changed, 9 insertions, 9 deletions

diff --git a/libbuild2/functions-project-name.cxx b/libbuild2/functions-project-name.cxx
index 86206b0..145e62c 100644
--- a/libbuild2/functions-project-name.cxx
+++ b/libbuild2/functions-project-name.cxx
@@ -13,46 +13,46 @@ namespace build2
   {
     function_family f (m, "project_name");
 
-    f["string"] = [](project_name p) {return move (p).string ();};
+    f["string"] += [](project_name p) {return move (p).string ();};
 
-    f["base"] = [](project_name p, optional<string> ext)
+    f["base"] += [](project_name p, optional<string> ext)
     {
       return ext ? p.base (ext->c_str ()) : p.base ();
     };
 
-    f["base"] = [](project_name p, names ext)
+    f["base"] += [](project_name p, names ext)
     {
       return p.base (convert<string> (move (ext)).c_str ());
     };
 
-    f["extension"] = &project_name::extension;
-    f["variable"]  = &project_name::variable;
+    f["extension"] += &project_name::extension;
+    f["variable"]  += &project_name::variable;
 
     // Project name-specific overloads from builtins.
     //
     function_family b (m, "builtin");
 
-    b[".concat"] = [](project_name n, string s)
+    b[".concat"] += [](project_name n, string s)
     {
       string r (move (n).string ());
       r += s;
       return r;
     };
 
-    b[".concat"] = [](string s, project_name n)
+    b[".concat"] += [](string s, project_name n)
     {
       s += n.string ();
       return s;
     };
 
-    b[".concat"] = [](project_name n, names ns)
+    b[".concat"] += [](project_name n, names ns)
     {
       string r (move (n).string ());
       r += convert<string> (move (ns));
       return r;
     };
 
-    b[".concat"] = [](names ns, project_name n)
+    b[".concat"] += [](names ns, project_name n)
     {
       string r (convert<string> (move (ns)));
       r += n.string ();