Clojure（read-line）返回nil;不提示 [英] Clojure's (read-line) returns nil; does not prompt

问题描述

我正在开发我的第一个正确的Clojure程序 - 一个象棋游戏。我有以下：

 （defn human-move [board] 
（board-utils / print-board ）
（printEnter your move，like this：'E7 E5'...）
（loop [raw-move（terminal-input）] ;;（read-line） $ b（printlnI just receivedraw-move）
（if（re-matches＃[AH] [1-8] \s [AH] [1-8]raw-move）
（parse-move raw-move）
（do 
（println格式不正确，应该有字母，数字，空格，字母和最后数字）
打印再试一次：）
（recur（read-line））））））
  

请注意 read-line 被注释掉并替换为 terminal-input 的位置。 read-line 给我一个NullPointerException，因此用于诊断目的：

  
（printnnreceivedwhatnot））
（printnninput）
（printnninput 
  

然后，当我调用 human-move 。

  ... 
 + --- + --- + --- + --- + -  + --- + --- + --- + 
 | P | P | P | P | P | P | P | P | 
 + --- + --- + --- + --- + --- + --- + --- + --- + 
 | R | N | B | Q | K | B | N | R | 
 + --- + --- + --- + --- + --- + --- + --- + --- + 
输入您的移动，如下所示：'E7 E5'...输入
收到nil 
我刚收到nil 
  

从来没有机会输入内容作为输入。这是Java，我会开始玩垃圾收集器的小游戏（调用 Scanner.next（），例如），但与Clojure我不知道什么除了将（flush）放入其中。

对于值得的，这是与SLIME。 p>

---

我也尝试了 terminal-input 提供虚拟数据，得知我显然使用 loop / recur 不正确。我没有彻底调查过，因为我已经分心的 read-line 问题。

b
$ b

提前感谢。

解决方案

这将与swank-clojure 1.4.0 -SNAPSHOT如果你在swank.core / with-read-line-support中调用read-line，就像这样

  with-read-line-support（println一行来自Emacs：（read-line））
  

https://github.com/technomancy/swank-clojure/commit/f4a1eebc4d34f2ff473c4e5350f889ec356f5168

I'm working on my first proper Clojure program--a chess game. I have the following:

(defn human-move [board]
  (board-utils/print-board board)
  (print "Enter your move, like this: 'E7 E5' ...")
  (loop [raw-move (terminal-input)] ;;(read-line)]
    (println "I just received" raw-move)
    (if (re-matches #"[A-H][1-8]\s[A-H][1-8]" raw-move)
      (parse-move raw-move)
      (do
        (println "Invalid format! There should be a letter, number, space, letter, and final number.")
        (print "Try again: ")
        (recur (read-line))))))

Note the place where read-line is commented out and replaced by terminal-input. read-line was giving me a NullPointerException, so for diagnostic purposes:

(defn terminal-input []
  (println "input")
  (let [whatnot (read-line)]
    (println "received" whatnot)
    whatnot))

Then, when I call human-move.

...
+---+---+---+---+---+---+---+---+
| P | P | P | P | P | P | P | P |
+---+---+---+---+---+---+---+---+
| R | N | B | Q | K | B | N | R |
+---+---+---+---+---+---+---+---+
Enter your move, like this: 'E7 E5' ...input
received nil
I just received nil

I never got a chance to type something in as input. Were this Java, I'd start playing little games with the garbage collector (calling Scanner.next(), for instance), but with Clojure I didn't know what to do besides putting the (flush) in there.

For what it's worth, this is with SLIME.

---

I also tried to have terminal-input provide dummy data, and learned that I'm apparently using loop/recur incorrectly. I haven't investigated it super-thoroughly though, since I've been distracted by the read-line issues.

Thanks in advance.

解决方案

This will work now with swank-clojure 1.4.0-SNAPSHOT if you wrap the call to read-line in swank.core/with-read-line-support like this

(with-read-line-support (println "a line from Emacs:" (read-line))

https://github.com/technomancy/swank-clojure/commit/f4a1eebc4d34f2ff473c4e5350f889ec356f5168

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