为什么要编译这段代码:
triples( [], _,_,_)->
[];
triples( Self, X, Y, none )->
[ Result || Result = { X, Y, _} <- Self ].
报告:
./simple_graph.erl:63: Warning: variable 'X' is unused
./simple_graph.erl:63: Warning: variable 'Y' is unused
./simple_graph.erl:64: Warning: variable 'X' is unused
./simple_graph.erl:64: Warning: variable 'X' shadowed in generate
./simple_graph.erl:64: Warning: variable 'Y' is unused
./simple_graph.erl:64: Warning: variable 'Y' shadowed in generate
并返回错误的结果:完全自我.
可以在特定字段中获取值为null的所有三元组吗？所有date_of_birth的人都等于null？
[
"type": "/people/person",
"date_of_birth":null,
"name":null
]
eyeryone!我有一个ejabberd的问题.Ejabberd mod_register配置有:
[{access, register}]
当我发送:
<body rid='1833385270' xmlns='http://jabber.org/protocol/httpbind' sid='ddc858306087c89bb1b95f6d507811f2068932cf'>
<iq to='intive.com' type='set' id='reg2' xmlns='jabber:client'>
<query xmlns='jabber:iq:register'>
<username>test_auto</username>
<password>test_auto</password>
</query>
</iq>
</body>
我明白了:
<body xmlns="http://jabber.org/protocol/httpbind">
<iq xmlns="jabber:client" from="bla.com" to="test1@bla.com/29309356411303308653389982" id="reg2" type="error">
<query xmlns="jabber:iq:register">
<username>test_auto</username>
<password>test_auto</password>
</query><error code="403" type="auth">
<forbidden xmlns="urn:ietf:params:xml:ns:xmpp-stanzas"/></error>
</iq>
</body>
我做错了什么？