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 * Copyright (C) 2007-2019 Artima, Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Automatically generated Scala interpreter transcript from:
 *
 * Programming in Scala (Fourth Edition)
 * by Martin Odersky, Lex Spoon, Bill Venners
 *
 * http://booksites.artima.com/programming_in_scala_4ed
 */


scala> var increase = (x: Int) => x + 1
increase: Int => Int = $$Lambda$740/277155095@34451ed8

scala> increase(10)
res0: Int = 11

scala> increase = (x: Int) => x + 9999
mutated increase

scala> increase(10)
res1: Int = 10009

scala> increase = (x: Int) => {
         println("We")
         println("are")
         println("here!")
         x + 1
       }
mutated increase

scala> increase(10)
We
are
here!
res2: Int = 11

scala> val someNumbers = List(-11, -10, -5, 0, 5, 10)
someNumbers: List[Int] = List(-11, -10, -5, 0, 5, 10)

scala> someNumbers.foreach((x: Int) => println(x))
-11
-10
-5
0
5
10

scala> someNumbers.filter((x: Int) => x > 0)
res4: List[Int] = List(5, 10)

scala> someNumbers.filter((x) => x > 0)
res5: List[Int] = List(5, 10)

scala> someNumbers.filter(x => x > 0)
res6: List[Int] = List(5, 10)

scala> someNumbers.filter(_ > 0)
res7: List[Int] = List(5, 10)

scala> someNumbers.filter(x => x > 0)
res8: List[Int] = List(5, 10)

scala> val f = _ + _
               ^
       error: missing parameter type for expanded function ((<x$1: error>, x$2) => x$1.$plus(x$2))
                   ^
       error: missing parameter type for expanded function ((<x$1: error>, <x$2: error>) => x$1.$plus(x$2))

scala> val f = (_: Int) + (_: Int)
f: (Int, Int) => Int = $$Lambda$806/1880726960@274b0c2a

scala> f(5, 10)
res9: Int = 15

scala> def sum(a: Int, b: Int, c: Int) = a + b + c
sum: (a: Int, b: Int, c: Int)Int

scala> sum(1, 2, 3)
res10: Int = 6

scala> val a = sum _
a: (Int, Int, Int) => Int = $$Lambda$815/1469492757@123372f4

scala> a(1, 2, 3)
res11: Int = 6

scala> a.apply(1, 2, 3)
res12: Int = 6

scala> val b = sum(1, _: Int, 3)
b: Int => Int = $$Lambda$816/1278632956@64f248ea

scala> b(2)
res13: Int = 6

scala> val c = sum
               ^
       error: missing argument list for method sum
       Unapplied methods are only converted to functions when a function type is expected.
       You can make this conversion explicit by writing `sum _` or `sum(_,_,_)` instead of `sum`.

scala> val d = sum _
d: (Int, Int, Int) => Int = $$Lambda$817/489693281@7a4729e6

scala> d(10, 20, 30)
res14: Int = 60

scala> (x: Int) => x + more
                       ^
       error: not found: value more

scala> var more = 1
more: Int = 1

scala> val addMore = (x: Int) => x + more
addMore: Int => Int = $$Lambda$823/1244142304@55c445e5

scala> addMore(10)
res16: Int = 11

scala> more = 9999
mutated more

scala> addMore(10)
res17: Int = 10009

scala> val someNumbers = List(-11, -10, -5, 0, 5, 10)
someNumbers: List[Int] = List(-11, -10, -5, 0, 5, 10)

scala> var sum = 0
sum: Int = 0

scala> sum
res19: Int = -11

scala>   def makeIncreaser(more: Int) = (x: Int) => x + more

makeIncreaser: (more: Int)Int => Int

scala> val inc1 = makeIncreaser(1)
inc1: Int => Int = $$Lambda$841/33422693@403d9a5b

scala> val inc9999 = makeIncreaser(9999)
inc9999: Int => Int = $$Lambda$841/33422693@10359f3

scala> inc1(10)
res20: Int = 11

scala> inc9999(10)
res21: Int = 10009

scala> def echo(args: String*) = 
         for (arg <- args) println(arg)
echo: (args: String*)Unit

scala> echo()

scala> echo("one")
one

scala> echo("hello", "world!")
hello
world!

scala> val seq = Seq("What's", "up", "doc?")
seq: Seq[String] = List(What's, up, doc?)

scala> echo(seq)
            ^
       error: type mismatch;
        found   : Seq[String]
        required: String

scala> echo(seq: _*)
What's
up
doc?

scala> def speed(distance: Float, time: Float): Float =
         distance / time
speed: (distance: Float, time: Float)Float

scala> speed(100, 10)
res27: Float = 10.0

scala> speed(distance = 100, time = 10)
res28: Float = 10.0

scala> speed(time = 10, distance = 100)
res29: Float = 10.0

scala>   def boom(x: Int): Int = 
           if (x == 0) throw new Exception("boom!")
           else boom(x - 1) + 1

boom: (x: Int)Int

scala>  def bang(x: Int): Int = 
          if (x == 0) throw new Exception("bang!")
          else bang(x - 1)

bang: (x: Int)Int