Smart indenting after enter when line ends with ':'.

src/source.cc

@@ -1534,6 +1534,35 @@ bool Source::ClangViewParse::on_key_press_event(GdkEventKey* key) {
           }
         }
       }
+      //Indenting after ':'
+      else if(*iter==':') {
+        auto previous_sentence_iter=get_buffer()->get_iter_at_line(iter.get_line());
+        while(previous_sentence_iter && (*previous_sentence_iter==tab_char || previous_sentence_iter.ends_line())) {
+          previous_sentence_iter.backward_char();
+        }
+        if(!previous_sentence_iter.ends_line())
+          previous_sentence_iter.forward_char();
+        Gtk::TextIter start_of_previous_sentence_iter;
+        if(find_start_of_closed_expression(previous_sentence_iter, start_of_previous_sentence_iter)) {
+          std::smatch sm;
+          auto start_previous_sentence=get_line_before(start_of_previous_sentence_iter);
+          if(std::regex_match(start_previous_sentence, sm, tabs_regex)) {
+            if(tabs.size()==(sm[1].str().size()+tab_size)) {
+              auto start_line_iter=get_buffer()->get_iter_at_line(iter.get_line());
+              auto start_line_plus_tab_size=start_line_iter;
+              for(size_t c=0;c<tab_size;c++)
+                start_line_plus_tab_size.forward_char();
+              get_buffer()->erase(start_line_iter, start_line_plus_tab_size);
+            }
+            else {
+              get_source_buffer()->insert_at_cursor("\n"+tabs+tab);
+              scroll_to(get_source_buffer()->get_insert());
+              get_source_buffer()->end_user_action();
+              return true;
+            }
+          }
+        }
+      }
       get_source_buffer()->insert_at_cursor("\n"+tabs);
       scroll_to(get_source_buffer()->get_insert());
       get_source_buffer()->end_user_action();