moduleceylon.ast.core1.2.2
ceylon.ast.core
classFunctionDeclaration
extends AnyFunction
OverviewPackageInitializerAttributesMethods

A function declaration.

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

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

In any case, the declaration must explicitly specify a type; a ‘function’ modifier (FunctionModifier) 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
FunctionDeclaration(MemberName name, Type|VoidModifier|FunctionModifier|DynamicModifier type, [Parameters+] parameterLists, TypeParameters? typeParameters = null, TypeConstraint[] typeConstraints = [], Annotations annotations = ...)
Parameters:
  • name

    The name of the declared program element, if present.

  • type

    The type of the declared function.

    This can be:

    • a Type,
    • a ‘void’ modifier (VoidModifier) for a function that does not return a value,
    • a ‘function’ modifier (FunctionModifier) for a function with inferred return type (which is illegal for declarations without definition, but not a syntactic restriction), or
    • a ‘dynamic’ modifier (DynamicModifier) for a dynamically typed function.
  • parameterLists

    The parameter lists. A function must have at least one, but may also have several parameter lists.

  • typeParameters = null

    The type parameters of the function, if any.

  • typeConstraints = []

    The type constraints placed upon the function’s type parameters, if any.

  • annotations = Annotations()

    The annotations on the declaration.

Attributes
annotationsshared actual Annotations annotations

The annotations on the declaration.

Refines Declaration.annotations
childrenshared actual [Annotations, Type|VoidModifier|FunctionModifier|DynamicModifier, LIdentifier, <TypeParameters|Parameters|TypeConstraint>*] children

The child nodes of this node.

Refines AnyFunction.children ultimately refines Node.children
definitionshared actual Null definition

A function declaration has no definition.

Refines AnyFunction.definition ultimately refines TypedDeclaration.definition
hashshared 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 removal of the 32 highest order bits, before returning the value to the caller.

Refines Object.hash
nameshared actual MemberName name

The name of the declared program element, if present.

Refines AnyFunction.name ultimately refines Declaration.name
parameterListsshared actual [Parameters+] parameterLists

The parameter lists. A function must have at least one, but may also have several parameter lists.

Refines AnyFunction.parameterLists
typeshared actual Type|VoidModifier|FunctionModifier|DynamicModifier type

The type of the declared function.

This can be:

  • a Type,
  • a ‘void’ modifier (VoidModifier) for a function that does not return a value,
  • a ‘function’ modifier (FunctionModifier) for a function with inferred return type (which is illegal for declarations without definition, but not a syntactic restriction), or
  • a ‘dynamic’ modifier (DynamicModifier) for a dynamically typed function.
Refines AnyFunction.type ultimately refines TypedDeclaration.type
typeConstraintsshared actual TypeConstraint[] typeConstraints

The type constraints placed upon the function’s type parameters, if any.

Refines AnyFunction.typeConstraints
typeParametersshared actual TypeParameters? typeParameters

The type parameters of the function, if any.

Refines AnyFunction.typeParameters
Inherited Attributes
Attributes inherited from: AnyFunction
children, definition, name, parameterLists, type, typeConstraints, typeParameters
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
copyshared FunctionDeclaration copy(MemberName name = ..., Type|VoidModifier|FunctionModifier|DynamicModifier type = ..., [Parameters+] parameterLists = ..., TypeParameters? typeParameters = ..., TypeConstraint[] typeConstraints = ..., Annotations annotations = ...)
Parameters:
  • name = this.name
  • type = this.type
  • parameterLists = this.parameterLists
  • typeParameters = this.typeParameters
  • typeConstraints = this.typeConstraints
  • annotations = this.annotations
equalsshared actual Boolean equals(Object that)

Determine if two values are equal. 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. 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
transformshared 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
visitshared 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