From 149bafa97b3c93b5116090d2834f0c19e6face95 Mon Sep 17 00:00:00 2001
From: Josh Ourisman <josh@joshourisman.com>
Date: Fri, 1 Oct 2010 16:17:04 -0400
Subject: [PATCH] added ability to append new column passing a callable as the
 value that will be applied to every row; w/ test

---
 tablib/core.py | 9 +++++++++
 test_tablib.py | 7 +++++++
 2 files changed, 16 insertions(+)

diff --git a/tablib/core.py b/tablib/core.py
index 8f74975..dfb8027 100644
--- a/tablib/core.py
+++ b/tablib/core.py
@@ -177,6 +177,15 @@ class Dataset(object):
 			self._validate(row)
 			self._data.append(tuple(row))
 		elif col is not None:
+			col = list(col)
+			if self.headers:
+				header = [col.pop(0)]
+			else:
+				header = []
+			if len(col) == 1 and callable(col[0]):
+				col = map(col[0], self._data)
+			col = tuple(header + col)
+				
 			self._validate(col=col)
 
 			if self.headers:
diff --git a/test_tablib.py b/test_tablib.py
index 67b693d..a315642 100755
--- a/test_tablib.py
+++ b/test_tablib.py
@@ -102,6 +102,13 @@ class TablibTestCase(unittest.TestCase):
 
 		self.assertRaises(tablib.InvalidDimensions, data.append, col=new_col)
 
+	def test_add_callable_column(self):
+		"""Verify adding column with values specified as callable."""
+		new_col = ['first_again', lambda x: x[0]]
+		self.founders.append(col=new_col)
+
+		self.assertTrue(map(lambda x: x[0] == x[-1], self.founders))
+
 
 	def test_header_slicing(self):
 		"""Verify slicing by headers."""