Index: trytond/trytond/tests/test_tools.py
===================================================================

--- a/trytond/trytond/tests/test_tools.py
+++ b/trytond/tests/test_tools.py
@@ -3,12 +3,13 @@
 #this repository contains the full copyright notices and license terms.

 import unittest
+import doctest
 import datetime
 import sql
 import sql.operators

 from trytond.tools import reduce_ids, safe_eval, datetime_strftime, \
-    reduce_domain
+    reduce_domain, decimal_


 class ToolsTestCase(unittest.TestCase):
@@ -117,4 +118,5 @@
     suite = unittest.TestSuite()
     for testcase in (ToolsTestCase,):
         suite.addTests(func(testcase))
+    suite.addTest(doctest.DocTestSuite(decimal_))
     return suite

Index: trytond/trytond/tools/__init__.py
===================================================================

--- a/trytond/trytond/tools/__init__.py
+++ b/trytond/trytond/tools/__init__.py
@@ -2,6 +2,7 @@
 #this repository contains the full copyright notices and license terms.
 from .misc import *
 from .datetime_strftime import *
+from .decimal_ import *


 class ClassProperty(property):

Index: trytond/trytond/tools/decimal_.py
===================================================================
new file mode 100644

--- /dev/null
+++ b/trytond/trytond/tools/decimal_.py
@@ -0,0 +1,36 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+import tokenize
+from io import StringIO
+
+# code snippet taken from http://docs.python.org/library/tokenize.html
+
+
+def decistmt(s):
+    """Substitute Decimals for floats in a string of statements.
+
+    >>> from decimal import Decimal
+    >>> s = 'print +21.3e-5*-.1234/81.7'
+    >>> decistmt(s)
+    u"print +Decimal (u'21.3e-5')*-Decimal (u'.1234')/Decimal (u'81.7')"
+
+    >>> exec(s)
+    -3.21716034272e-07
+    >>> exec(decistmt(s))
+    -3.217160342717258261933904529E-7
+    """
+    result = []
+    # tokenize the string
+    g = tokenize.generate_tokens(StringIO(s.decode('utf-8')).readline)
+    for toknum, tokval, _, _, _ in g:
+        # replace NUMBER tokens
+        if toknum == tokenize.NUMBER and '.' in tokval:
+            result.extend([
+                (tokenize.NAME, 'Decimal'),
+                (tokenize.OP, '('),
+                (tokenize.STRING, repr(tokval)),
+                (tokenize.OP, ')')
+            ])
+        else:
+            result.append((toknum, tokval))
+    return tokenize.untokenize(result)