1 files changed, 32 insertions, 0 deletions
diff --git a/cmd2/utils.py b/cmd2/utils.py
index 6abab94c..dbe39213 100644
--- a/cmd2/utils.py
+++ b/cmd2/utils.py
@@ -2,6 +2,7 @@
 # coding=utf-8
 """Shared utility functions"""
 
+import collections
 from . import constants
 
 def strip_ansi(text: str) -> str:
@@ -12,6 +13,7 @@ def strip_ansi(text: str) -> str:
     """
     return constants.ANSI_ESCAPE_RE.sub('', text)
 
+
 def strip_quotes(arg: str) -> str:
     """ Strip outer quotes from a string.
 
@@ -23,3 +25,33 @@ def strip_quotes(arg: str) -> str:
     if len(arg) > 1 and arg[0] == arg[-1] and arg[0] in constants.QUOTES:
         arg = arg[1:-1]
     return arg
+
+
+def namedtuple_with_defaults(typename, field_names, default_values=()):
+    """
+    Convenience function for defining a namedtuple with default values
+
+    From: https://stackoverflow.com/questions/11351032/namedtuple-and-default-values-for-optional-keyword-arguments
+
+    Examples:
+        >>> Node = namedtuple_with_defaults('Node', 'val left right')
+        >>> Node()
+        Node(val=None, left=None, right=None)
+        >>> Node = namedtuple_with_defaults('Node', 'val left right', [1, 2, 3])
+        >>> Node()
+        Node(val=1, left=2, right=3)
+        >>> Node = namedtuple_with_defaults('Node', 'val left right', {'right':7})
+        >>> Node()
+        Node(val=None, left=None, right=7)
+        >>> Node(4)
+        Node(val=4, left=None, right=7)
+    """
+    T = collections.namedtuple(typename, field_names)
+    T.__new__.__defaults__ = (None,) * len(T._fields)
+    if isinstance(default_values, collections.Mapping):
+        prototype = T(**default_values)
+    else:
+        prototype = T(*default_values)
+    T.__new__.__defaults__ = tuple(prototype)
+    return T
+