I'm following "Programming in Scala", on Chapter 10 Type Hierarchy (http://www.artima.com/pins1ed/composition-and-inheritance.html).
I'm receiving the following error in my Scala interactive shell:
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)
^
Does anyone have any idea why 1) My object cannot recognize the companion class ("extends Element") 2) The method is unable to call another method within the same class/companion object?
I have my class set up as follows:
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 }
Thanks for your help!
Update: I tried :paste instead of :load, and still get the following error message:
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)
^
looking through :help
scala> :help
...
:load <path> interpret lines in a file
:paste [-raw] [path] enter paste mode or paste a file
:load seems to be just an interpreter. Try :paste
scala> :paste Element.scala
Pasting file Element.scala...
defined class Element
defined object Element