Merge pull request #335 from python-cmd2/completion_tweaks

Added padding to display matches for visual appeal

Author: kmvanbrunt

cmd2.py

@@ -1758,6 +1758,29 @@ def _redirect_complete(self, text, line, begidx, endidx, compfunc):
         # Call the command's completer function
         return compfunc(text, line, begidx, endidx)
 
+    @staticmethod
+    def _pad_matches_to_display(matches_to_display):
+        """
+        Adds padding to the matches being displayed as tab completion suggestions.
+        The default padding of readline/pyreadine is small and not visually appealing
+        especially if matches have spaces. It appears very squished together.
+        :param matches_to_display: the matches being padded
+        :return: the padded matches and length of padding
+        """
+        if rl_type == RlType.GNU:
+            # Add 2 to the padding of 2 that readline uses for a total of 4.
+            padding = 2 * ' '
+            return [cur_match + padding for cur_match in matches_to_display], len(padding)
+
+        elif rl_type == RlType.PYREADLINE:
+            # Add 3 to the padding of 1 that pyreadline uses for a total of 4.
+            padding = 3 * ' '
+            return [cur_match + padding for cur_match in matches_to_display], len(padding)
+
+        else:
+            # This function is meaningless without readline
+            return matches_to_display, 0
+
     def _display_matches_gnu_readline(self, substitution, matches, longest_match_length):
         """
         Prints a match list using GNU readline's rl_display_match_list()
@@ -1783,6 +1806,10 @@ def _display_matches_gnu_readline(self, substitution, matches, longest_match_len
             else:
                 matches_to_display = matches
 
+            # Add padding for visual appeal
+            matches_to_display, padding_length = self._pad_matches_to_display(matches_to_display)
+            longest_match_length += padding_length
+
             # We will use readline's display function (rl_display_match_list()), so we
             # need to encode our string as bytes to place in a C array.
             if six.PY3:
@@ -1829,6 +1856,9 @@ def _display_matches_pyreadline(self, matches):
             else:
                 matches_to_display = matches
 
+            # Add padding for visual appeal
+            matches_to_display, _ = self._pad_matches_to_display(matches_to_display)
+
             # Display the matches
             orig_pyreadline_display(matches_to_display)
 
@@ -2088,7 +2118,7 @@ def complete(self, text, state):
                         # before we alter them. That way the suggestions will reflect how we parsed
                         # the token being completed and not how readline did.
                         if len(self.display_matches) == 0:
-                            self.display_matches = self.completion_matches
+                            self.display_matches = copy.copy(self.completion_matches)
 
                         # Check if we need to remove text from the beginning of tab completions
                         if text_to_remove: