moduleceylon.ast.core1.3.3
Source Code
ceylon.ast.core
classValueDeclaration
extends AnyValue
OverviewPackageInitializerAttributesMethods

A value declaration.

A value declaration declares the name and type of the value, but doesn’t provide a definition for it. There are several possible reasons for this:

  • The value can be a formal attribute and be a member of an abstract class
    or an interface, and subtypes have to provide the definition.
  • The value can be the declaration of a class or function parameter that only listed the name (and potentially a default value).
  • The value can be forward-declared, and the definition will be provided later.

In any case, the declaration must explicitly specify a type; a Modifier indicating type inference cannot be used. (The ’dynamic’ modifier counts as a “type” here, indicating not the inference, but rather the absense of typing information.)

no subtypes hierarchy

Initializer
ValueDeclaration(MemberName name, Type|VariadicType|DynamicModifier type, Annotations annotations = ...)
Parameters:
  • name

    The name of the declared value.

  • type

    The type of the declared value.

    This can be:

    • a proper Type,
    • a variadic type for the declaration of a variadic parameter, or
    • a ’dynamic’ modifier (DynamicModifier) to indicate the absence of a type.
  • annotations = tations = Ann

    The annotations of the declared value.

Attributes
annotationsSource Codeshared actual Annotations annotations

The annotations of the declared value.

Refines Declaration.annotations
childrenSource Codeshared actual [Annotations, Type|VariadicType|DynamicModifier, LIdentifier] children

The child nodes of this node.

Refines AnyValue.children ultimately refines Node.children
definitionSource Codeshared actual Null definition

A value declaration has no definition.

Refines TypedDeclaration.definition
hashSource Codeshared actual Integer hash

The hash value of the value, which allows the value to be an element of a hash-based set or key of a hash-based map. Implementations must respect the constraint that:

  • if x==y then x.hash==y.hash.

Therefore, a class which refines equals must also refine hash.

In general, hash values vary between platforms and between executions of the same program.

Note that when executing on a Java Virtual Machine, the 64-bit Integer value returned by an implementation of hash is truncated to a 32-bit integer value by taking the exclusive disjunction of the 32 lowest-order bits with the 32 highest-order bits, before returning the value to the caller.

Refines Object.hash
nameSource Codeshared actual MemberName name

The name of the declared value.

Refines TypedDeclaration.name ultimately refines Declaration.name
typeSource Codeshared actual Type|VariadicType|DynamicModifier type

The type of the declared value.

This can be:

  • a proper Type,
  • a variadic type for the declaration of a variadic parameter, or
  • a ’dynamic’ modifier (DynamicModifier) to indicate the absence of a type.
Refines TypedDeclaration.type
Inherited Attributes
Attributes inherited from: AnyValue
children
Attributes inherited from: Declaration
annotations, name
Attributes inherited from: Node
children, data, string
Attributes inherited from: Object
hash, string
Attributes inherited from: TypedDeclaration
definition, name, type
Methods
copySource Codeshared ValueDeclaration copy(MemberName name = ..., Type|VariadicType|DynamicModifier type = ..., Annotations annotations = ...)
Parameters:
  • name = erName na
  • type = difier ty
  • annotations = annotations = th
equalsSource Codeshared actual Boolean equals(Object that)

Determine if two values are equal.

For any two non-null objects x and y, x.equals(y) may be written as:

x == y

Implementations should respect the constraints that:

  • if x===y then x==y (reflexivity),
  • if x==y then y==x (symmetry),
  • if x==y and y==z then x==z (transitivity).

Furthermore it is recommended that implementations ensure that if x==y then x and y have the same concrete class.

A class which explicitly refines equals() is said to support value equality, and the equality operator == is considered much more meaningful for such classes than for a class which simply inherits the default implementation of identity equality from Identifiable.

Note that an implementation of equals() that always returns false does satisfy the constraints given above, as long as the class does not inherit Identifiable. Therefore, in very rare cases where there is no reasonable definition of value equality for a class, for example, function references (Callable), it is acceptable for equals() to be defined to return false for every argument.

Refines Object.equals
transformSource Codeshared actual Result transform<out Result>(Transformer<Result> transformer)

Transform this node with the given transformer by calling the appropriate transformX method on the transformer.

If you have a Node node that’s actually an LIdentifier instance, then the runtime will call LIdentifier.transform; therefore, this method is by nature narrowing. This means that if transformer is a NarrowingTransformer, calling node.transform(transformer) is equivalent to calling transformer.transformNode(node). On the other hand, if transformer is a WideningTransformer, then the two operations are very different.

Refines Node.transform
visitSource Codeshared actual void visit(Visitor visitor)

Visit this node with the given visitor. Calls the appropriate visitX method on the visitor.

Refines Node.visit
Inherited Methods
Methods inherited from: Node
copyExtraInfoTo(), delete(), get(), getObject(), put(), remove(), set(), transform(), transformChildren(), visit(), visitChildren()
Methods inherited from: Object
equals