Packages

  • package root

    This is the documentation for the Scala standard library.

    This is the documentation for the Scala standard library.

    Package structure

    The scala package contains core types like Int, Float, Array or Option which are accessible in all Scala compilation units without explicit qualification or imports.

    Notable packages include:

    Other packages exist. See the complete list on the right.

    Additional parts of the standard library are shipped as separate libraries. These include:

    • scala.reflect - Scala's reflection API (scala-reflect.jar)
    • scala.xml - XML parsing, manipulation, and serialization (scala-xml.jar)
    • scala.swing - A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)
    • scala.util.parsing - Parser combinators (scala-parser-combinators.jar)

    Automatic imports

    Identifiers in the scala package and the scala.Predef object are always in scope by default.

    Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example, List is an alias for scala.collection.immutable.List.

    Other aliases refer to classes provided by the underlying platform. For example, on the JVM, String is an alias for java.lang.String.

    Definition Classes
    root
  • package scala

    Core Scala types.

    Core Scala types. They are always available without an explicit import.

    Definition Classes
    root
  • package util
    Definition Classes
    scala
  • package control
    Definition Classes
    util
  • object TailCalls

    Methods exported by this object implement tail calls via trampolining.

    Methods exported by this object implement tail calls via trampolining. Tail calling methods have to return their result using done or call the next method using tailcall. Both return a TailRec object. The result of evaluating a tailcalling function can be retrieved from a Tailrec value using method result. Implemented as described in "Stackless Scala with Free Monads" http://blog.higher-order.com/assets/trampolines.pdf

    Here's a usage example:

    import scala.util.control.TailCalls._

def isEven(xs: List[Int]): TailRec[Boolean] =
  if (xs.isEmpty) done(true) else tailcall(isOdd(xs.tail))

def isOdd(xs: List[Int]): TailRec[Boolean] =
 if (xs.isEmpty) done(false) else tailcall(isEven(xs.tail))

isEven((1 to 100000).toList).result

def fib(n: Int): TailRec[Int] =
  if (n < 2) done(n) else for {
    x <- tailcall(fib(n - 1))
    y <- tailcall(fib(n - 2))
  } yield (x + y)

fib(40).result
    Definition Classes
    control
  • Call
  • Cont
  • Done
  • TailRec

case class Cont[A, B](a: TailRec[A], f: (A) ⇒ TailRec[B]) extends TailRec[B] with Product with Serializable

Internal class representing a continuation with function A => TailRec[B]. It is needed for the flatMap to be implemented.

Attributes
protected
Source
TailCalls.scala
Linear Supertypes
Serializable, java.io.Serializable, Product, Equals, TailRec[B], AnyRef, Any
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. Cont
  2. Serializable
  3. Serializable
  4. Product
  5. Equals
  6. TailRec
  7. AnyRef
  8. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
  1. Hide All
  2. Show All
Visibility
  1. Public
  2. All

Instance Constructors

  1. new Cont(a: TailRec[A], f: (A) ⇒ TailRec[B])

Value Members

  1. final def !=(arg0: Any): Boolean

    Test two objects for inequality.

    Test two objects for inequality.

    returns

    true if !(this == that), false otherwise.

    Definition Classes
    AnyRef → Any
  2. final def ##(): Int

    Equivalent to x.hashCode except for boxed numeric types and null.

    Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.

    returns

    a hash value consistent with ==

    Definition Classes
    AnyRef → Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from Cont[A, B] to any2stringadd[Cont[A, B]] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Cont[A, B], B)
    Implicit
    This member is added by an implicit conversion from Cont[A, B] to ArrowAssoc[Cont[A, B]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean

    The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    AnyRef → Any
  6. val a: TailRec[A]
  7. final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type T0.

    Cast the receiver object to be of type T0.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown

    ClassCastException if the receiver object is not an instance of the erasure of type T0.

  8. def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @native() @throws( ... )
    Note

    not specified by SLS as a member of AnyRef

  9. def ensuring(cond: (Cont[A, B]) ⇒ Boolean, msg: ⇒ Any): Cont[A, B]
    Implicit
    This member is added by an implicit conversion from Cont[A, B] to Ensuring[Cont[A, B]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  10. def ensuring(cond: (Cont[A, B]) ⇒ Boolean): Cont[A, B]
    Implicit
    This member is added by an implicit conversion from Cont[A, B] to Ensuring[Cont[A, B]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: Boolean, msg: ⇒ Any): Cont[A, B]
    Implicit
    This member is added by an implicit conversion from Cont[A, B] to Ensuring[Cont[A, B]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: Boolean): Cont[A, B]
    Implicit
    This member is added by an implicit conversion from Cont[A, B] to Ensuring[Cont[A, B]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (that) is a reference to the receiver object (this).

    Tests whether the argument (that) is a reference to the receiver object (this).

    The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:

    • It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.
    • For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false.
    • null.eq(null) returns true.

    When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

    returns

    true if the argument is a reference to the receiver object; false otherwise.

    Definition Classes
    AnyRef
  14. val f: (A) ⇒ TailRec[B]
  15. def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
    Note

    not specified by SLS as a member of AnyRef

  16. final def flatMap[B](f: (B) ⇒ TailRec[B]): TailRec[B]

    Continue the computation with f and merge the trampolining of this computation with that of f.

    Continue the computation with f and merge the trampolining of this computation with that of f.

    Definition Classes
    TailRec
  17. def formatted(fmtstr: String): String

    Returns string formatted according to given format string.

    Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

    Implicit
    This member is added by an implicit conversion from Cont[A, B] to StringFormat[Cont[A, B]] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  18. final def getClass(): Class[_]

    Returns the runtime class representation of the object.

    Returns the runtime class representation of the object.

    returns

    a class object corresponding to the runtime type of the receiver.

    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  19. final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is T0.

    Test whether the dynamic type of the receiver object is T0.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

    Definition Classes
    Any
  20. final def map[B](f: (B) ⇒ B): TailRec[B]

    Continue the computation with f.

    Continue the computation with f.

    Definition Classes
    TailRec
  21. final def ne(arg0: AnyRef): Boolean

    Equivalent to !(this eq that).

    Equivalent to !(this eq that).

    returns

    true if the argument is not a reference to the receiver object; false otherwise.

    Definition Classes
    AnyRef
  22. final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  23. final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  24. final def result: B

    Returns the result of the tailcalling computation.

    Returns the result of the tailcalling computation.

    Definition Classes
    TailRec
    Annotations
    @tailrec()
  25. final def resume: scala.Either[() ⇒ TailRec[B], B]

    Returns either the next step of the tailcalling computation, or the result if there are no more steps.

    Returns either the next step of the tailcalling computation, or the result if there are no more steps.

    Definition Classes
    TailRec
    Annotations
    @tailrec()
  26. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  27. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  28. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  29. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @throws( ... )
  30. def →[B](y: B): (Cont[A, B], B)
    Implicit
    This member is added by an implicit conversion from Cont[A, B] to ArrowAssoc[Cont[A, B]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Inherited from Serializable

Inherited from java.io.Serializable

Inherited from Product

Inherited from Equals

Inherited from TailRec[B]

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from Cont[A, B] to any2stringadd[Cont[A, B]]

Inherited by implicit conversion StringFormat from Cont[A, B] to StringFormat[Cont[A, B]]

Inherited by implicit conversion Ensuring from Cont[A, B] to Ensuring[Cont[A, B]]

Inherited by implicit conversion ArrowAssoc from Cont[A, B] to ArrowAssoc[Cont[A, B]]

Ungrouped