inliner warnings with Map literal and -optimize

scala在编译&优化的时候,有时候会返回个inline warning.但是,实际上我们写代码已经不能再优化了. 比如如下这个例子:

yu:~ yu$ scala -version
Scala code runner version 2.11.7 -- Copyright 2002-2013, LAMP/EPFL
yu:~ yu$ scala -optimize -Yinline-warnings
Welcome to Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_05).
Type in expressions to have them evaluated.
Type :help for more information.

scala> object O { Map(
     |   "a" -> 0, "b" -> 1, "c" -> 2, "d" -> 3, "e" -> 4,
     |   "a" -> 0, "b" -> 1, "c" -> 2, "d" -> 3, "e" -> 4,
     |   "a" -> 0, "b" -> 1, "c" -> 2, "d" -> 3, "e" -> 4,
     |   "f" -> 5, "g" -> 6, "h" -> 7, "i" -> 8) }
warning: At the end of the day, could not inline @inline-marked method ->$extension
warning: At the end of the day, could not inline @inline-marked method ->$extension
warning: At the end of the day, could not inline @inline-marked method ->$extension
warning: At the end of the day, could not inline @inline-marked method ->$extension
defined object O

我们可以看到有个issue ,讲的就是这件事.它是12年底建立的,但一直没啥好的回答...可怜我为了关掉这个warning连带好几个其它warning都不能用了.

不过,今年五月终于有结果了.

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a workaround of false negative in missing interpolator warning

一般情况下,我们会倾向于打开各种warning,以便规范我们的代码.不过,scala有时候有些warning也是蛮扯的.比如这么一段

$ scala -Xlint:missing-interpolator
Welcome to Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_05).
Type in expressions to have them evaluated.
Type :help for more information.

scala> val key="value"; println("$key")
<console>:12: warning: possible missing interpolator: detected interpolated identifier `$key`
        println("$key")
                ^
$key
key: String = value

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scala 读写文件

scala 一般用于网络上消息的处理,比如读写 mongodb, 处理 http request. 但偶尔写个 script, 还是要读写个文件的.

scala 包装了一个 Source 类,可以读取各种来源的数据, url, file 都可以. 但似乎并没有对写数据做什么处理.

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