setup.py : define egg versions in buildout

buildout.cfg

@@ -4,6 +4,7 @@
 [buildout]
 develop = .
 parts = interpreter test
+versions = versions
 
 [interpreter]
 recipe = zc.recipe.egg
@@ -13,3 +14,10 @@ eggs = dream
 [test]
 recipe = zc.recipe.testrunner
 eggs = dream
+
+[versions]
+# python 2 compatible
+pyparsing = 1.5.7
+
+# 2.4.1 does not work for me
+rpy2 = >=2.3,<2.4

setup.py

@@ -13,10 +13,10 @@ setup(
         'SimPy>=3',
         'xlrd',
         'xlwt',
-        'pyparsing==1.5.7', # latest python2 compatible version
+        'pyparsing',
         'pydot',
         'numpy',
-        'rpy2>=2.3,<2.4', # 2.4.1 does not work for me
+        'rpy2'
     ],
     entry_points=("""
     [console_scripts]