Ruby iterators now automatically return an Enumerator if no block is given - allows very cool code ..

src/lay/lay/doc/programming/ruby_binding.xml

@@ -499,6 +499,16 @@ public:
 a = A::new
 a.each { |i| ... }</pre>
 
+  <p>
+  If no block is given, an Enumerator object is created. Enumerators
+  are a Ruby feature. Enumerators support many convenient methods
+  like sort, inject, collect, select etc. Here is an example:
+  </p>
+
+  <pre>
+# turns all elements returned by the iterator into strings and sorts them
+sorted = a.each.collect(&amp;:to_s).sort</pre>
+
   <p>
   Iterators match very well between C++ and Ruby so there are no real issues here.
   The return type of the iterators is mapped to Ruby's block arguments using the

src/rba/rba/rba.cc

@@ -89,7 +89,8 @@ public:
   {
     std::vector<tl::BacktraceElement> bt;
     bt.push_back (tl::BacktraceElement (rb_sourcefile (), rb_sourceline ()));
-    rba_get_backtrace_from_array (rb_funcall (rb_mKernel, rb_intern ("caller"), 0), bt, 0);
+    static ID id_caller = rb_intern ("caller");
+    rba_get_backtrace_from_array (rb_funcall (rb_mKernel, id_caller, 0), bt, 0);
     return bt;
   }
 
@@ -113,7 +114,8 @@ public:
     //  But the purpose is a relative compare, so efficiency is not sacrificed here
     //  for unnecessary consistency.
     int d = 1;
-    VALUE backtrace = rb_funcall (rb_mKernel, rb_intern ("caller"), 0);
+    static ID id_caller = rb_intern ("caller");
+    VALUE backtrace = rb_funcall (rb_mKernel, id_caller, 0);
     if (TYPE (backtrace) == T_ARRAY) {
       d += RARRAY_LEN(backtrace);
     }
@@ -933,16 +935,18 @@ method_adaptor (int mid, int argc, VALUE *argv, VALUE self, bool ctor)
 
       if (p) {
 
+        static ID id_set = rb_intern ("set");
+
         VALUE signal_handler = p->signal_handler (meth);
 
         if (rb_block_given_p ()) {
 
           VALUE proc = rb_block_proc ();
           RB_GC_GUARD (proc);
-          ret = rba_funcall2_checked (signal_handler, rb_intern ("set"), 1, &proc);
+          ret = rba_funcall2_checked (signal_handler, id_set, 1, &proc);
 
         } else if (argc > 0) {
-          ret = rba_funcall2_checked (signal_handler, rb_intern ("set"), argc, argv);
+          ret = rba_funcall2_checked (signal_handler, id_set, argc, argv);
         } else {
           ret = signal_handler;
         }
@@ -991,6 +995,24 @@ method_adaptor (int mid, int argc, VALUE *argv, VALUE self, bool ctor)
         p->set (obj, true, false, true, self);
       }
 
+    } else if (meth->ret_type ().is_iter () && ! rb_block_given_p ()) {
+
+      //  calling an iterator method without block -> deliver an enumerator using "to_enum"
+
+      static ID id_to_enum = rb_intern ("to_enum");
+
+      VALUE method_sym = ID2SYM (rb_intern (meth->primary_name ().c_str ()));
+
+      if (argc == 0) {
+        ret = rba_funcall2_checked (self, id_to_enum, 1, &method_sym);
+      } else {
+        std::vector<VALUE> new_args;
+        new_args.reserve (size_t (argc + 1));
+        new_args.push_back (method_sym);
+        new_args.insert (new_args.end (), argv, argv + argc);
+        ret = rba_funcall2_checked (self, id_to_enum, argc + 1, new_args.begin ().operator-> ());
+      }
+
     } else {
 
       void *obj = 0;

testdata/ruby/basic_testcore.rb

@@ -733,6 +733,8 @@ class Basic_TestClass < TestBase
     arr = []
     b.each_b_copy { |bb| arr.push(bb.b2) } 
     assert_equal(arr, ["a", "y", "uu"])
+    # through enumerator
+    assert_equal(b.each_b_copy.collect(&:b2), ["a", "y", "uu"])
 
     arr = []
     b.each_b_copy { |bb| bb.b5(bb.b2 + "x"); arr.push(bb.b2) } 
@@ -745,6 +747,8 @@ class Basic_TestClass < TestBase
     arr = []
     b.each_b_cref { |bb| arr.push(bb.b2) } 
     assert_equal(arr, ["a", "y", "uu"])
+    # through enumerator
+    assert_equal(b.each_b_cref.collect(&:b2), ["a", "y", "uu"])
 
     arr = []
     # this works, since the "const B &" will be converted to a copy
@@ -759,6 +763,8 @@ class Basic_TestClass < TestBase
     arr = []
     b.each_b_cptr { |bb| arr.push(bb.b2) } 
     assert_equal(arr, ["a", "y", "uu"])
+    # through enumerator
+    assert_equal(b.each_b_cptr.collect(&:b2), ["a", "y", "uu"])
 
     arr = []
     # const references cannot be modified
@@ -778,6 +784,8 @@ class Basic_TestClass < TestBase
     arr = []
     b.each_b_ref { |bb| arr.push(bb.b2) } 
     assert_equal(arr, ["a", "y", "uu"])
+    # through enumerator
+    assert_equal(b.each_b_ref.collect(&:b2), ["a", "y", "uu"])
 
     arr = []
     b.each_b_ref { |bb| bb.b5(bb.b2 + "x"); arr.push(bb.b2) } 
@@ -790,6 +798,8 @@ class Basic_TestClass < TestBase
     arr = []
     b.each_b_ptr { |bb| arr.push(bb.b2) } 
     assert_equal(arr, ["ax", "yx", "uux"])
+    # through enumerator
+    assert_equal(b.each_b_ptr.collect(&:b2), ["ax", "yx", "uux"])
 
     arr = []
     b.each_b_ptr { |bb| bb.b5(bb.b2 + "x"); arr.push(bb.b2) } 

testdata/ruby/dbPolygonTest.rb

@@ -67,6 +67,8 @@ class DBPolygon_TestClass < TestBase
     arr = []
     a.each_point_hull { |p| arr.push( p.to_s ) }
     assert_equal( arr, ["5,-10", "5,15", "20,15", "20,-10"] )
+    # with enumerator
+    assert_equal( a.each_point_hull.collect(&:to_s), ["5,-10", "5,15", "20,15", "20,-10"] )
 
     b = a.dup
 
@@ -130,6 +132,8 @@ class DBPolygon_TestClass < TestBase
     arr = []
     a.each_point_hole(0) { |p| arr.push( p.to_s ) }
     assert_equal( arr, ["1,2", "2,2", "2,6"] )
+    # with enumerator
+    assert_equal( a.each_point_hole(0).collect(&:to_s), ["1,2", "2,2", "2,6"] )
 
     arr = []
     a.each_edge { |p| arr.push( p.to_s ) }