2 files changed, 16 insertions, 3 deletions
diff --git a/qtip/base/constant.py b/qtip/base/constant.py
index 187f0706..76481b47 100644
--- a/qtip/base/constant.py
+++ b/qtip/base/constant.py
@@ -8,8 +8,8 @@
 ##############################################################################
 
 
-class AlgoName(object):
-    """algorithm names"""
+class FormulaName(object):
+    """formula names"""
     ARITHMETIC_MEAN = 'arithmetic mean'
     WEIGHTED_ARITHMETIC_MEAN = 'weighted arithmetic mean'
     GEOMETRIC_MEAN = 'geometric mean'
@@ -37,7 +37,7 @@ class PropName(object):
     # spec
     SECTIONS = 'sections'
     WEIGHT = 'weight'
-    ALGORITHM = 'algorithm'
+    FORMULA = 'formula'
     METRICS = 'metrics'
     WORKLOADS = 'workloads'
     # plan
diff --git a/qtip/base/error.py b/qtip/base/error.py
index d364c532..01a7f7a6 100644
--- a/qtip/base/error.py
+++ b/qtip/base/error.py
@@ -21,3 +21,16 @@ class NotFound(QtipError):
     def __init__(self, module, package='qtip'):
         self.package = package
         self.module = module
+
+
+class ToBeDoneError(QtipError):
+    """something still to be done"""
+    def __init__(self, method, module):
+        self.method = method
+        self.module = module
+
+
+def make_tbd(method, module='qtip'):
+    def tbd():
+        raise ToBeDoneError(method, module)
+    return tbd