小妹最近刚开始接触 scala 在此之前 有接触过java 但对 functional programming没有接触过 最近读到 scala的英文教学书里的 symbol literal 实在不是很了解 去爬了很多文发现他很像 ruby 里的 symbol 根据自己的理解 主要的概念 就是说 symbol可以自订identifier (如果也什麽错误或观念需要厘清的可以指证我 谢谢~~~) 但 scala书中提到 For instance, you might want to define a method that updates a record in a database: scala> def updateRecordByName(r: Symbol, value: Any) { // code goes here } updateRecordByName: (Symbol,Any)Unit The method takes as parameters a symbol indicating the name of a record field and a value with which the field should be updated in the record. In a dynamically typed language, you could invoke this operation passing an undeclared field identifier to the method, but in Scala this would not compile: scala> updateRecordByName(favoriteAlbum, "OK Computer") <console>:6: error: not found: value favoriteAlbum updateRecordByName(favoriteAlbum, "OK Computer") Instead, and almost as concisely, you can pass a symbol literal: scala> updateRecordByName('favoriteAlbum, "OK Computer") 想请问各位大大 这边有点不懂QQ 为什麽直接写favoriteAlbum会有错呢?? symbol完之後为何就没有错误呢? 附上pdf之网址 在5.2 p114 的地方 http://www.cs.ucsb.edu/~benh/260/Programming-in-Scala.pdf 谢谢大大的帮助了 !!!! O___Q --

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