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 Metalevels to any2stringadd[Metalevels] performed by method any2stringadd in scala.Predef.

   Definition Classes

   any2stringadd

4.  def ->[B](y: B): (Metalevels, B)

   Implicit

   This member is added by an implicit conversion from Metalevels to ArrowAssoc[Metalevels] 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.  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.

7.  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

   @throws( ... )

   Note

   not specified by SLS as a member of AnyRef

8.  def ensuring(cond: (Metalevels) ⇒ Boolean, msg: ⇒ Any): Metalevels

   Implicit

   This member is added by an implicit conversion from Metalevels to Ensuring[Metalevels] performed by method Ensuring in scala.Predef.

   Definition Classes

   Ensuring

9.  def ensuring(cond: (Metalevels) ⇒ Boolean): Metalevels

   Implicit

   This member is added by an implicit conversion from Metalevels to Ensuring[Metalevels] performed by method Ensuring in scala.Predef.

   Definition Classes

   Ensuring

10.  def ensuring(cond: Boolean, msg: ⇒ Any): Metalevels

    Implicit

    This member is added by an implicit conversion from Metalevels to Ensuring[Metalevels] performed by method Ensuring in scala.Predef.

    Definition Classes

    Ensuring

11.  def ensuring(cond: Boolean): Metalevels

    Implicit

    This member is added by an implicit conversion from Metalevels to Ensuring[Metalevels] performed by method Ensuring in scala.Predef.

    Definition Classes

    Ensuring

12.  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

13.  def equals(arg0: Any): Boolean

    The equality method for reference types.

    The equality method for reference types. Default implementation delegates to eq.

    See also equals in scala.Any.

    returns

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

    Definition Classes

    AnyRef → Any

14.  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

15.  def formatted(fmtstr: String): String

    Implicit

    This member is added by an implicit conversion from Metalevels to StringFormat[Metalevels] performed by method StringFormat in scala.Predef.

    Definition Classes

    StringFormat

    Annotations

    @inline()

16.  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

17.  def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

    the hash code value for this object.

    Definition Classes

    AnyRef → Any

18.  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

19.  val metalevels: tools.nsc.Global.Transformer { ... /* 4 definitions in type refinement */ }

    Makes sense of cross-stage bindings.

    Makes sense of cross-stage bindings.

    ---

    Analysis of cross-stage bindings becomes convenient if we introduce the notion of metalevels. Metalevel of a tree is a number that gets incremented every time you reify something and gets decremented when you splice something. Metalevel of a symbol is equal to the metalevel of its definition.

    Example 1. Consider the following snippet:

    reify { val x = 2 // metalevel of symbol x is 1, because it's declared inside reify val y = reify{x} // metalevel of symbol y is 1, because it's declared inside reify // metalevel of Ident(x) is 2, because it's inside two reifies y.splice // metalevel of Ident(y) is 0, because it's inside a designator of a splice }

    Cross-stage bindings are introduced when symbol.metalevel != curr_metalevel. Both bindings introduced in Example 1 are cross-stage.

    Depending on what side of the inequality is greater, the following situations might occur:

    1) symbol.metalevel < curr_metalevel. In this case reifier will generate a free variable that captures both the name of the symbol (to be compiled successfully) and its value (to be run successfully). For example, x in Example 1 will be reified as follows: Ident(newFreeVar("x", IntTpe, x))

    2) symbol.metalevel > curr_metalevel. This leads to a metalevel breach that violates intuitive perception of splicing. As defined in macro spec, splicing takes a tree and inserts it into another tree - as simple as that. However, how exactly do we do that in the case of y.splice? In this very scenario we can use dataflow analysis and inline it, but what if y were a var, and what if it were calculated randomly at runtime?

    This question has a genuinely simple answer. Sure, we cannot resolve such splices statically (i.e. during macro expansion of reify), but now we have runtime toolboxes, so noone stops us from picking up that reified tree and evaluating it at runtime (in fact, this is something that Expr.splice does transparently).

    This is akin to early vs late binding dilemma. The prior is faster, plus, the latter (implemented with reflection) might not work because of visibility issues or might be not available on all platforms. But the latter still has its uses, so I'm allowing metalevel breaches, but introducing the -Xlog-runtime-evals to log them.

    upd. We no longer do that. In case of a runaway splice inside a reify, one will get a static error. Why? Unfortunately, the cute idea of transparently converting between static and dynamic splices has failed. 1) Runtime eval that services dynamic splices requires scala-compiler.jar, which might not be on library classpath 2) Runtime eval incurs a severe performance penalty, so it'd better to be explicit about it

    ---

    As we can see, the only problem is the fact that lhs'es of splice can be code blocks that can capture variables from the outside. Code inside the lhs of an splice is not reified, while the code from the enclosing reify is.

    Hence some bindings become cross-stage, which is not bad per se (in fact, some cross-stage bindings have sane semantics, as in the example above). However this affects freevars, since they are delicate inter-dimensional beings that refer to both current and next planes of existence. When splicing tears the fabric of the reality apart, some freevars have to go single-dimensional to retain their sanity.

    Example 2. Consider the following snippet:

    reify { val x = 2 reify{x}.splice }

    Since the result of the inner reify is wrapped in a splice, it won't be reified together with the other parts of the outer reify, but will be inserted into that result verbatim.

    The inner reify produces an Expr[Int] that wraps Ident(freeVar("x", IntTpe, x)). However the freevar the reification points to will vanish when the compiler processes the outer reify. That's why we need to replace that freevar with a regular symbol that will point to reified x.

    Example 3. Consider the following fragment:

    reify { val x = 2 val y = reify{x} y.splice }

    In this case the inner reify doesn't appear next to splice, so it will be reified together with x. This means that no special processing is needed here.

    Example 4. Consider the following fragment:

    reify { val x = 2 { val y = 2 val z = reify{reify{x + y}} z.splice }.splice }

    The reasoning from Example 2 still holds here - we do need to inline the freevar that refers to x. However, we must not touch anything inside the splice'd block, because it's not getting reified.

20.  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

21.  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

    Note

    not specified by SLS as a member of AnyRef

22.  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

    Note

    not specified by SLS as a member of AnyRef

23.  final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes

    AnyRef

24.  def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

    a String representation of the object.

    Definition Classes

    AnyRef → Any

25.  final def wait(): Unit

    Definition Classes

    AnyRef

    Annotations

    @throws( ... )

26.  final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes

    AnyRef

    Annotations

    @throws( ... )

27.  final def wait(arg0: Long): Unit

    Definition Classes

    AnyRef

    Annotations

    @throws( ... )

28.  def →[B](y: B): (Metalevels, B)

    Implicit

    This member is added by an implicit conversion from Metalevels to ArrowAssoc[Metalevels] performed by method ArrowAssoc in scala.Predef.

    Definition Classes

    ArrowAssoc