don't break if "decimal" is not available

git-svn-id: https://pycam.svn.sourceforge.net/svnroot/pycam/trunk@763 bbaffbd6-741e-11dd-a85d-61de82d9cad9

src/pycam/Geometry/Point.py

@@ -22,7 +22,6 @@ along with PyCAM.  If not, see <http://www.gnu.org/licenses/>.
 """
 
 from pycam.Geometry.utils import epsilon, sqrt, number
-from decimal import Decimal
 
 def _is_near(x, y):
     return abs(x - y) < epsilon

src/pycam/Geometry/utils.py

@@ -20,15 +20,22 @@ You should have received a copy of the GNU General Public License
 along with PyCAM.  If not, see <http://www.gnu.org/licenses/>.
 """
 
-import decimal
+# use the "decimal" module for fixed precision numbers (only for debugging)
+_use_precision = False
+
+
+# "decimal" is not available in some minimal installations of python2.6
+# (e.g. in Debian Lenny)
+try:
+    import decimal
+except ImportError:
+    _use_precision = False
+
 import math
 
 INFINITE = 100000
 epsilon = 0.00001
 
-# use the "decimal" module for fixed precision numbers (only for debugging)
-_use_precision = False
-
 
 # the lambda functions below are more efficient than function definitions