API reference - Class Value

Notation used in Ruby API documentation

Module: tl

Description: Encapsulates a value (preferably a plain data type) in an object

This class is provided to 'box' a value (encapsulate the value in an object). This class is required to interface to pointer or reference types in a method call. By using that class, the method can alter the value and thus implement 'out parameter' semantics. The value may be 'nil' which acts as a null pointer in pointer type arguments. This class has been introduced in version 0.22.

Public constructors

new Value ptrnewConstructs a nil object.
new Value ptrnew(variant value)Constructs a non-nil object with the given value.

Public methods

void_createEnsures the C++ object is created
void_destroyExplicitly destroys the object
[const]bool_destroyed?Returns a value indicating whether the object was already destroyed
[const]bool_is_const_object?Returns a value indicating whether the reference is a const reference
void_manageMarks the object as managed by the script side.
void_unmanageMarks the object as no longer owned by the script side.
voidassign(const Value other)Assigns another object to self
[const]new Value ptrdupCreates a copy of self
[const]stringto_sConvert this object to a string
[const]variantvalueGets the actual value.
voidvalue=(variant value)Set the actual value.

Deprecated methods (protected, public, static, non-static and constructors)

voidcreateUse of this method is deprecated. Use _create instead
voiddestroyUse of this method is deprecated. Use _destroy instead
[const]booldestroyed?Use of this method is deprecated. Use _destroyed? instead
[const]boolis_const_object?Use of this method is deprecated. Use _is_const_object? instead

Detailed description

_create

Signature: void _create

Description: Ensures the C++ object is created

Use this method to ensure the C++ object is created, for example to ensure that resources are allocated. Usually C++ objects are created on demand and not necessarily when the script object is created.

_destroy

Signature: void _destroy

Description: Explicitly destroys the object

Explicitly destroys the object on C++ side if it was owned by the script interpreter. Subsequent access to this object will throw an exception. If the object is not owned by the script, this method will do nothing.

_destroyed?

Signature: [const] bool _destroyed?

Description: Returns a value indicating whether the object was already destroyed

This method returns true, if the object was destroyed, either explicitly or by the C++ side. The latter may happen, if the object is owned by a C++ object which got destroyed itself.

_is_const_object?

Signature: [const] bool _is_const_object?

Description: Returns a value indicating whether the reference is a const reference

This method returns true, if self is a const reference. In that case, only const methods may be called on self.

_manage

Signature: void _manage

Description: Marks the object as managed by the script side.

After calling this method on an object, the script side will be responsible for the management of the object. This method may be called if an object is returned from a C++ function and the object is known not to be owned by any C++ instance. If necessary, the script side may delete the object if the script's reference is no longer required.

Usually it's not required to call this method. It has been introduced in version 0.24.

_unmanage

Signature: void _unmanage

Description: Marks the object as no longer owned by the script side.

Calling this method will make this object no longer owned by the script's memory management. Instead, the object must be managed in some other way. Usually this method may be called if it is known that some C++ object holds and manages this object. Technically speaking, this method will turn the script's reference into a weak reference. After the script engine decides to delete the reference, the object itself will still exist. If the object is not managed otherwise, memory leaks will occur.

Usually it's not required to call this method. It has been introduced in version 0.24.

assign

Signature: void assign (const Value other)

Description: Assigns another object to self

create

Signature: void create

Description: Ensures the C++ object is created

Use of this method is deprecated. Use _create instead

Use this method to ensure the C++ object is created, for example to ensure that resources are allocated. Usually C++ objects are created on demand and not necessarily when the script object is created.

destroy

Signature: void destroy

Description: Explicitly destroys the object

Use of this method is deprecated. Use _destroy instead

Explicitly destroys the object on C++ side if it was owned by the script interpreter. Subsequent access to this object will throw an exception. If the object is not owned by the script, this method will do nothing.

destroyed?

Signature: [const] bool destroyed?

Description: Returns a value indicating whether the object was already destroyed

Use of this method is deprecated. Use _destroyed? instead

This method returns true, if the object was destroyed, either explicitly or by the C++ side. The latter may happen, if the object is owned by a C++ object which got destroyed itself.

dup

Signature: [const] new Value ptr dup

Description: Creates a copy of self

Python specific notes:
This method also implements '__copy__' and '__deepcopy__'.

is_const_object?

Signature: [const] bool is_const_object?

Description: Returns a value indicating whether the reference is a const reference

Use of this method is deprecated. Use _is_const_object? instead

This method returns true, if self is a const reference. In that case, only const methods may be called on self.

new

(1) Signature: [static] new Value ptr new

Description: Constructs a nil object.

Python specific notes:
This method is the default initializer of the object.

(2) Signature: [static] new Value ptr new (variant value)

Description: Constructs a non-nil object with the given value.

This constructor has been introduced in version 0.22.

Python specific notes:
This method is the default initializer of the object.

to_s

Signature: [const] string to_s

Description: Convert this object to a string

Python specific notes:
This method is also available as 'str(object)'.

value

Signature: [const] variant value

Description: Gets the actual value.

Python specific notes:
The object exposes a readable attribute 'value'. This is the getter.

value=

Signature: void value= (variant value)

Description: Set the actual value.

Python specific notes:
The object exposes a writable attribute 'value'. This is the setter.