小编Fen*_*eng的帖子

有时我可以得到一个连接,有时它会失败

MongoDB shell version: 2.4.3
connecting to: test
Wed Jul  3 13:07:09.878 Socket recv() errno:104 Connection reset by peer 127.0.0.1:27017
Wed Jul  3 13:07:09.878 SocketException: remote: 127.0.0.1:27017 error: 9001 socket exception [1] server [127.0.0.1:27017]
Wed Jul  3 13:07:09.878 DBClientCursor::init call() failed
Wed Jul  3 13:07:09.880 JavaScript execution failed: Error: DBClientBase::findN: transport error: 127.0.0.1:27017 ns: admin.$cmd query: { whatsmyuri: 1 } at src/mongo/shell/mongo.js:L112
exception: connect failed

这按预期工作

[97,98].map(function(x){String.fromCharCode(x)})
// [ 'a', 'b' ]

但输出跟随线是意外的

[97,98].map(String.fromCharCode)
// [ 'a\u0000\u0000', 'b\u0001\u0000' ]

use和 和有@before_compile什么区别？两者都可用于将一些代码注入当前模块。

处理元组的方式似乎不一致:

defmodule A do
  defmacro a(x) do
    IO.inspect x
    quote do end
  end
end

A.a {:a, :b}版画{:a, :b}不如预期,但A.a {:a}打印{:{}, [line: 2], [:a]}

代码有什么问题吗？看起来binding不适用iterate？

(def ^:dynamic *step* 1)

(defn incr [n] (+ n *step*))

(take 3 (binding [*step* 2] (iterate incr 1)))

给

'(1 2 3)

不

'(1 3 5)