interpreter.check

Type in expressions to have them evaluated.
Type :help for more information.

scala> 

scala> // basics

scala> 3+4
res0: Int = 7

scala> def gcd(x: Int, y: Int): Int = {
          if (x == 0) y
          else if (y == 0) x
          else gcd(y%x, x)
}
gcd: (x: Int, y: Int)Int

scala> val five = gcd(15,35)
five: Int = 5

scala> var x = 1
x: Int = 1

scala> x = 2
x: Int = 2

scala> val three = x+1
three: Int = 3

scala> type anotherint = Int
defined type alias anotherint

scala> val four: anotherint = 4
four: anotherint = 4

scala> val bogus: anotherint = "hello"
<console>:8: error: type mismatch;
 found   : String("hello")
 required: anotherint
    (which expands to)  Int
       val bogus: anotherint = "hello"
                               ^

scala> trait PointlessTrait
defined trait PointlessTrait

scala> val (x,y) = (2,3)
x: Int = 2
y: Int = 3

scala> println("hello")
hello

scala> 

scala> // ticket #1513

scala> val t1513 = Array(null)
t1513: Array[Null] = Array(null)

scala> // ambiguous toString problem from #547

scala> val atom = new scala.xml.Atom()
atom: scala.xml.Atom[Unit] = ()

scala> // overriding toString problem from #1404

scala> class S(override val toString : String)
defined class S

scala> val fish = new S("fish")
fish: S = fish

scala> // Test that arrays pretty print nicely.

scala> val arr = Array("What's", "up", "doc?")
arr: Array[String] = Array(What's, up, doc?)

scala> // Test that arrays pretty print nicely, even when we give them type Any

scala> val arrInt : Any = Array(1,2,3)
arrInt: Any = Array(1, 2, 3)

scala> // Test that nested arrays are pretty-printed correctly

scala> val arrArrInt : Any = Array(Array(1, 2), Array(3, 4))
arrArrInt: Any = Array(Array(1, 2), Array(3, 4))

scala> 

scala> // implicit conversions

scala> case class Foo(n: Int)
defined class Foo

scala> case class Bar(n: Int)
defined class Bar

scala> implicit def foo2bar(foo: Foo) = Bar(foo.n)
warning: there were 1 feature warnings; re-run with -feature for details
foo2bar: (foo: Foo)Bar

scala> val bar: Bar = Foo(3)
bar: Bar = Bar(3)

scala> 

scala> // importing from a previous result

scala> import bar._
import bar._

scala> val m = n
m: Int = 3

scala> 

scala> // stressing the imports mechanism

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> val one = 1
one: Int = 1

scala> 

scala> 

scala> val x1 = 1
x1: Int = 1

scala> val x2 = 1
x2: Int = 1

scala> val x3 = 1
x3: Int = 1

scala> val x4 = 1
x4: Int = 1

scala> val x5 = 1
x5: Int = 1

scala> val x6 = 1
x6: Int = 1

scala> val x7 = 1
x7: Int = 1

scala> val x8 = 1
x8: Int = 1

scala> val x9 = 1
x9: Int = 1

scala> val x10 = 1
x10: Int = 1

scala> val x11 = 1
x11: Int = 1

scala> val x12 = 1
x12: Int = 1

scala> val x13 = 1
x13: Int = 1

scala> val x14 = 1
x14: Int = 1

scala> val x15 = 1
x15: Int = 1

scala> val x16 = 1
x16: Int = 1

scala> val x17 = 1
x17: Int = 1

scala> val x18 = 1
x18: Int = 1

scala> val x19 = 1
x19: Int = 1

scala> val x20 = 1
x20: Int = 1

scala> 

scala> val two = one + x5
two: Int = 2

scala> 

scala> // handling generic wildcard arrays (#2386)

scala> // It's put here because type feedback is an important part of it.

scala> val xs: Array[_] = Array(1, 2)
xs: Array[_] = Array(1, 2)

scala> xs.size
res2: Int = 2

scala> xs.head
res3: Any = 1

scala> xs filter (_ == 2)
res4: Array[_] = Array(2)

scala> xs map (_ => "abc")
res5: Array[String] = Array(abc, abc)

scala> xs map (x => x)
res6: Array[_] = Array(1, 2)

scala> xs map (x => (x, x))
warning: there were 1 feature warnings; re-run with -feature for details
warning: there were 1 feature warnings; re-run with -feature for details
res7: Array[(_$1, _$1)] forSome { type _$1 } = Array((1,1), (2,2))

scala> 

scala> // interior syntax errors should *not* go into multi-line input mode.

scala> // both of the following should abort immediately:

scala> def x => y => z
<console>:1: error: '=' expected but '=>' found.
       def x => y => z
             ^

scala> [1,2,3]
<console>:1: error: illegal start of definition
       [1,2,3]
       ^

scala> 

scala> 

scala> // multi-line XML

scala> <a>
<b
  c="c"
  d="dd"
/></a>
res8: scala.xml.Elem = 
<a>
<b c="c" d="dd"/></a>

scala> 

scala> 

scala> /*
  /*
    multi-line comment
  */
*/


You typed two blank lines.  Starting a new command.

scala> // multi-line string

scala> """
hello
there
"""
res12: String = 
"
hello
there
"

scala> 

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


You typed two blank lines.  Starting a new command.

scala> // defining and using quoted names should work (ticket #323)

scala> def `match` = 1
match: Int

scala> val x = `match`
x: Int = 1

scala> 

scala> // multiple classes defined on one line

scala> sealed class Exp; class Fact extends Exp; class Term extends Exp
defined class Exp
defined class Fact
defined class Term

scala> def f(e: Exp) = e match {  // non-exhaustive warning here
  case _:Fact => 3
}
<console>:18: warning: match is not exhaustive!
missing combination            Exp
missing combination           Term

       def f(e: Exp) = e match {  // non-exhaustive warning here
                       ^
f: (e: Exp)Int

scala> 

scala> 
plusOne: (x: Int)Int
res0: Int = 6
res0: String = after reset
<console>:8: error: not found: value plusOne
              plusOne(5) // should be undefined now
              ^