[map] Use hb_invoke() with pointer-to-method

src/hb-algs.hh

@@ -73,7 +73,7 @@ struct
   /* Pointer-to-member-function. */
   template <typename Appl, typename Val1, typename ...Vals> auto
   impl (Appl&& a, hb_priority<2>, Val1 &&v1, Vals &&...vs) const HB_AUTO_RETURN
-  (hb_deref_pointer (hb_forward<Val1> (v1)).*hb_forward<Appl> (a) (hb_forward<Vals> (vs)...))
+  ((hb_deref_pointer (hb_forward<Val1> (v1)).*hb_forward<Appl> (a)) (hb_forward<Vals> (vs)...))
 
   /* Pointer-to-member. */
   template <typename Appl, typename Val> auto
@@ -86,6 +86,9 @@ struct
   (hb_deref_pointer (hb_forward<Appl> (a)) (hb_forward<Vals> (vs)...))
 
   public:
+  template <typename Appl, typename Val1, typename ...Vals> auto
+  impl2 (Appl&& a, hb_priority<2>, Val1 &&v1, Vals &&...vs) const HB_AUTO_RETURN
+  (hb_deref_pointer (hb_forward<Val1> (v1)).*hb_forward<Appl> (a) (hb_forward<Vals> (vs)...))
 
   template <typename Appl, typename ...Vals> auto
   operator () (Appl&& a, Vals &&...vs) const HB_AUTO_RETURN

src/hb-map.hh

@@ -122,7 +122,7 @@ struct hb_hashmap_t
       return false;
     }
     + hb_iter (new_items, new_size)
-    | hb_apply ([] (item_t &_) { _.clear (); }) /* TODO make pointer-to-methods invokable. */
+    | hb_apply (&item_t::clear)
     ;
 
     unsigned int old_size = mask + 1;
@@ -193,7 +193,7 @@ struct hb_hashmap_t
       return;
     if (items)
       + hb_iter (items, mask + 1)
-      | hb_apply ([] (item_t &_) { _.clear (); }) /* TODO make pointer-to-methods invokable. */
+      | hb_apply (&item_t::clear)
       ;
 
     population = occupancy = 0;

src/test-algs.cc

@@ -34,6 +34,11 @@ test_func (int a, char **b)
   return b ? b[a] : nullptr;
 }
 
+struct A
+{
+  void a () {}
+};
+
 int
 main (int argc, char **argv)
 {
@@ -54,5 +59,8 @@ main (int argc, char **argv)
 
   hb_invoke (test_func, 0, nullptr);
 
+  A a;
+  hb_invoke (&A::a, a);
+
   return 0;
 }