Scala example source code file (interpreter.scala)

This example Scala source code file (interpreter.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

any, array, array, bar, exp, exp, fact, foo, foo, int, int, repltest, s, settings

The Scala interpreter.scala source code

import scala.tools.nsc._
import scala.tools.partest.ReplTest

object Test extends ReplTest {
  def code = <code>
// basics
3+4
def gcd(x: Int, y: Int): Int = {{
          if (x == 0) y
          else if (y == 0) x
          else gcd(y%x, x)
}}
val five = gcd(15,35)
var x = 1
x = 2
val three = x+1
type anotherint = Int
val four: anotherint = 4
val bogus: anotherint = "hello"
trait PointlessTrait
val (x,y) = (2,3)
println("hello")

// ticket #1513
val t1513 = Array(null)
// ambiguous toString problem from #547
val atom = new scala.xml.Atom()
// overriding toString problem from #1404
class S(override val toString : String)
val fish = new S("fish")
// Test that arrays pretty print nicely.
val arr = Array("What's", "up", "doc?") 
// Test that arrays pretty print nicely, even when we give them type Any
val arrInt : Any = Array(1,2,3)
// Test that nested arrays are pretty-printed correctly
val arrArrInt : Any = Array(Array(1, 2), Array(3, 4))

// implicit conversions
case class Foo(n: Int)
case class Bar(n: Int)
implicit def foo2bar(foo: Foo) = Bar(foo.n)
val bar: Bar = Foo(3)

// importing from a previous result
import bar._
val m = n

// stressing the imports mechanism
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1
val one = 1


val x1 = 1
val x2 = 1
val x3 = 1
val x4 = 1
val x5 = 1
val x6 = 1
val x7 = 1
val x8 = 1
val x9 = 1
val x10 = 1
val x11 = 1
val x12 = 1
val x13 = 1
val x14 = 1
val x15 = 1
val x16 = 1
val x17 = 1
val x18 = 1
val x19 = 1
val x20 = 1

val two = one + x5

// handling generic wildcard arrays (#2386)
// It's put here because type feedback is an important part of it.
val xs: Array[_] = Array(1, 2)
xs.size
xs.head
xs filter (_ == 2)
xs map (_ => "abc")
xs map (x => x)
xs map (x => (x, x))

// interior syntax errors should *not* go into multi-line input mode.
// both of the following should abort immediately:
def x => y => z
[1,2,3]


// multi-line XML
<a>
<b
  c="c"
  d="dd"
/></a>


/*
  /*
    multi-line comment
  */
*/


// multi-line string
"""
hello
there
"""

(1 +   // give up early by typing two blank lines


// defining and using quoted names should work (ticket #323)
def `match` = 1 
val x = `match` 

// multiple classes defined on one line
sealed class Exp; class Fact extends Exp; class Term extends Exp
def f(e: Exp) = e match {{  // non-exhaustive warning here
  case _:Fact => 3
}}

</code>.text

  def appendix() = {
    val settings = new Settings
    settings.classpath.value = sys.props("java.class.path")
    val interp = new Interpreter(settings)
    interp.interpret("def plusOne(x: Int) = x + 1")
    interp.interpret("plusOne(5)")
    interp.reset()
    interp.interpret("\"after reset\"")
    interp.interpret("plusOne(5) // should be undefined now")
  }
  
  appendix()
}