Scala 按字段处理案例类

我有一个模拟国际象棋游戏的模块，有以下两个类：

case class Pos(x: Char, y: Char)
abstract class Piece(player: Int, pos: Pos) 

我有一套

作品

：

val pieces: Set[Piece]

我想这样过滤它：

pieces.filter(piece => !(piece.pos == pos2))

但是，我遇到了以下错误：

Error:(45, 36) value pos is not a member of chess.Piece
    pieces.filter(piece => !(piece.pos == pos2))
                               ^

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为什么会这样？我不能用

.pos

引用

Piece

类型的变量吗？

发生这种情况是因为没有为Piece类设置getter

// No getters/setters created
abstract class Piece(player: Int, pos: Pos) 

// Only Getters created because constructor params are immutable 
abstract class Piece(val player: Int, val pos: Pos) 

// Both Getters & Setter created because constructor params are mutable 
abstract class Piece(var player: Int, var pos: Pos) 

---

发生这种情况是因为没有为您的Piece类设置getter

// No getters/setters created
abstract class Piece(player: Int, pos: Pos) 

// Only Getters created because constructor params are immutable 
abstract class Piece(val player: Int, val pos: Pos) 

// Both Getters & Setter created because constructor params are mutable 
abstract class Piece(var player: Int, var pos: Pos) 

---

你能展示抽象类的实现吗？你能展示抽象类的实现吗？