# [Zope-Checkins] Re: [Checkins] SVN: Products.Five/trunk/ Now you can use the old registry with the new API for registerig components.

```Indeed :)
```
```
On 29 Jul 2006, at 00:39, Benji York wrote:

```
```Florent Guillaume wrote:
```
```On 27 Jul 2006, at 16:15, Lennart Regebro wrote:
```
```Modified: Products.Five/trunk/site/localsite.py
===================================================================
```
--- Products.Five/trunk/site/localsite.py 2006-07-27 13:51:25 UTC (rev 69270) +++ Products.Five/trunk/site/localsite.py 2006-07-27 14:15:46 UTC (rev 69271)
```@@ -16,12 +16,26 @@
\$Id\$
"""

+from operator import xor
+def one_of_three(a, b, c):
```
+ # Logical table for a three part test where only one can be true:
```+    # 0 0 0: 0
+    # 0 0 1: 1
+    # 0 1 0: 1
+    # 0 1 1: 0
+    # 1 0 0: 1
+    # 1 0 1: 0
+    # 1 1 0: 0
+    # 1 1 1: 0
+    return xor(xor(a, b), c) and not (a and b and c)
```
Heh, boolean algebra is nice but sometimes integers convey the meaning much better:
```   return int(a)+int(b)+int(c) == 1
```
```

def only_one(*args):
return sum(bool(i) for i in args) == 1
--
Benji York
Senior Software Engineer
Zope Corporation
```
```
--
Florent Guillaume, Nuxeo (Paris, France)   Director of R&D
+33 1 40 33 71 59   http://nuxeo.com   [EMAIL PROTECTED]

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```