import re
rex = re.compile(r'^([^\\]*)(\\.[^.^$*+?{}\[\]|()\\]*)*[.^$*+?{}\[\]|()]', re.MULTILINE)
arr = [r"example", r"foo\.bar", r"e.ample", r"foo\\.bar", r"foo\\bar\.baz", r"foo\\bar.baz", r"foo(bar)"]
for s in arr:
print s, re.search(rex, s) != None
aW1wb3J0IHJlCgpyZXggPSByZS5jb21waWxlKHInXihbXlxcXSopKFxcLlteLl4kKis/e31cW1xdfCgpXFxdKikqWy5eJCorP3t9XFtcXXwoKV0nLCByZS5NVUxUSUxJTkUpCgphcnIgPSBbciJleGFtcGxlIiwgciJmb29cLmJhciIsIHIiZS5hbXBsZSIsIHIiZm9vXFwuYmFyIiwgciJmb29cXGJhclwuYmF6IiwgciJmb29cXGJhci5iYXoiLCByImZvbyhiYXIpIl0KCmZvciBzIGluIGFycjoKCXByaW50IHMsIHJlLnNlYXJjaChyZXgsIHMpICE9IE5vbmUKCgk=