第 10 章型階層 ( http://www.artima.com/pins1ed/composition-and-inheritance.html ) の「Programming in Scala」に従っています。
Scala インタラクティブ シェルで次のエラーが表示されます。
scala> :load Element.scala
Loading Element.scala...
<console>:11: error: not found: type Element
) extends Element
^
<console>:13: error: not found: type Element
private class LineElement(s: String) extends Element {
^
<console>:23: error: not found: type Element
) extends Element {
^
<console>:28: error: not found: type Element
def elem(contents: Array[String]): Element = new ArrayElement(contents)
^
<console>:30: error: not found: type Element
def elem(chr: Char, width: Int, height: Int): Element = new UniformElement(chr, width, height)
^
<console>:32: error: not found: type Element
def elem(line: String): Element = new LineElement(line)
^
<console>:7: error: not found: value Element
import Element.elem
^
<console>:16: error: not found: value elem
elem(this1.contents ++ that1.contents)
^
<console>:22: error: not found: value elem
elem(
^
<console>:30: error: not found: value elem
val left = elem(' ', (w - width) / 2, height)
^
<console>:31: error: not found: value elem
var right = elem(' ', w - width - left.width, height)
^
<console>:38: error: not found: value elem
val top = elem(' ', width, (h - height) / 2)
^
<console>:39: error: not found: value elem
var bot = elem(' ', width, h - height - top.height)
^
1) 私のオブジェクトがコンパニオン クラスを認識できない (「要素を拡張」) 2) メソッドが同じクラス/コンパニオン オブジェクト内の別のメソッドを呼び出せない理由は誰にもわかりますか?
クラスを次のように設定しています。
1 object Element {
2
3 private class ArrayElement(
4 val contents: Array[String]
5 ) extends Element
6
7 private class LineElement(s: String) extends Element {
8 val contents = Array(s)
9 override def width = s.length
10 override def height = 1
11 }
12
13 private class UniformElement(
14 ch: Char,
15 override val width: Int,
16 override val height: Int
17 ) extends Element {
18 private val line = ch.toString * width
19 def contents = Array.fill(height)(line)
20 }
21
22 def elem(contents: Array[String]): Element = new ArrayElement(contents)
23
24 def elem(chr: Char, width: Int, height: Int): Element = new UniformElement(chr, width, height)
25
26 def elem(line: String): Element = new LineElement(line)
27 }
28
29 import Element.elem
30 abstract class Element {
31 def contents: Array[String]
32
33 def width: Int = contents(0).length
34 def height: Int = contents.length
35
36 def above(that: Element): Element = {
37 val this1 = this widen that.width
38 val that1 = that widen this.width
39 elem(this1.contents ++ that1.contents)
40 }
41
42 def beside(that: Element): Element = {
43 val this1 = this heighten that.height
44 val that1 = that heighten this.height
45 elem(
46 for ((line1, line2) <- this1.contents zip that1.contents)
47 yield line1 + line2)
48 }
49
50 def widen(w: Int): Element =
51 if (w <= width) this
52 else {
53 val left = elem(' ', (w - width) / 2, height)
54 var right = elem(' ', w - width - left.width, height)
55 left beside this beside right
56 }
57
58 def heighten(h: Int): Element =
59 if (h <= height) this
60 else {
61 val top = elem(' ', width, (h - height) / 2)
62 var bot = elem(' ', width, h - height - top.height)
63 top above this above bot
64 }
65
66 override def toString = contents mkString "\n"
67 }
ご協力いただきありがとうございます！
更新: :load の代わりに :paste を試しましたが、次のエラー メッセージが表示されます。
scala> :paste Element.scala
Pasting file Element.scala...
<console>:44: error: not found: value elem
elem(this1.contents ++ that1.contents)
^
<console>:50: error: not found: value elem
elem(
^
<console>:58: error: not found: value elem
val left = elem(' ', (w - width) / 2, height)
^
<console>:59: error: not found: value elem
var right = elem(' ', w - width - left.width, height)
^
<console>:66: error: not found: value elem
val top = elem(' ', width, (h - height) / 2)
^
<console>:67: error: not found: value elem
var bot = elem(' ', width, h - height - top.height)
^