[toward py3k] rewrite dict.keys() and dict.values() (part of #2711624)
Python 3K will only expose iterators.
http://docs.python.org/3.0/whatsnew/3.0.html#views-and-iterators-instead-of-lists
try:
rtype, = __args__
except ValueError:
print 'USAGE: cubicweb-ctl shell <instance> detect_cycle.py -- <relation type>'
print
graph = {}
for fromeid, toeid in rql('Any X,Y WHERE X %s Y' % rtype):
graph.setdefault(fromeid, []).append(toeid)
from logilab.common.graph import get_cycles
for cycle in get_cycles(graph):
print 'cycle', '->'.join(str(n) for n in cycle)