Object

class Object extends Any

Call

Creates a new Object.

Obj := Object()
Obj := Object.Call()

Clone

Returns a shallow copy of an object.

Clone := Obj.Clone()

Each property or method owned by the object is copied into the clone. Object references are copied (like with a normal assignment), not the objects themselves; in other words, if a property contains a reference to an object, the clone will contain a reference to the same object.

Dynamic properties are copied, not invoked.

The clone has the same base object as the original object.

A TypeError is thrown if Obj is derived from an unsupported built-in type. This implementation of Clone supports Object, Class and Error objects. See also: Clone (Array), Clone (Map).

DefineProp

Defines a new own property.

Obj := Obj.DefineProp(Name, Descriptor)

Parameters

Name

Type: String

The name of the property.

Descriptor

Type: Object

An object with one of the following own properties, or both Get and Set:

Get: The function object to call when the property's value is retrieved.

Set: The function object to call when the property is assigned a value. Its second parameter is the value being assigned.

Call: The function object to call when the property is called.

Value: Any value to assign to the property.

Return Value

Type: Object

This method returns the target object.

Remarks

This method can be used to convert a value property to a dynamic property or vice versa, but it is not possible to specify both a value and accessor functions.

If any one of the accessor functions is omitted, behavior is inherited from a base object.

• An inherited value property is equivalent to a set of accessor functions which return or call the value, or store a new value in this. Note that a new value would overwrite any dynamic property in this itself, and override any inherited accessor functions.
• If no Set or value is defined or inherited, attempting to set the property will throw an exception.
• If no Call is defined or inherited, Get may be called to retrieve a function object, which is then called.
• If no Get is defined or inherited but there is a Call accessor function, the function itself becomes the property's value (read-only).

As with methods, the first parameter of Get, Set or Call is this (the target object). For Set, the second parameter is value (the value being assigned). These parameters are defined automatically by method and property definitions within a class, but must be defined explicitly if using normal functions. Any other parameters passed by the caller are appended to the parameter list.

The MaxParams and IsVariadic properties of the function objects are evaluated to determine whether the property may accept parameters. If MaxParams is 1 for Get or 2 for Set and IsVariadic is false or undefined, the property cannot accept parameters; they are instead forwarded to the __Item property of the object returned by get.

DeleteProp

Removes an own property from an object.

RemovedValue := Obj.DeleteProp(Name)

Parameters

Name

Type: String

A property name.

Return Value

Type: Any

This method returns the value of the removed property (blank if none).

GetOwnPropDesc

Returns a descriptor for a given own property, compatible with DefineProp.

Descriptor := Obj.GetOwnPropDesc(Name)

Parameters

Name

Type: String

A property name.

Return Value

Type: Object

For a dynamic property, the return value is a new object with an own property for each accessor function: Get, Set, Call. Each property is present only if the corresponding accessor function is defined in Obj itself. For a value property, the return value is a new object with a property named Value. In such cases, Obj.GetOwnPropDesc(Name).Value == Obj.%Name%.

Modifying the returned object has no effect on Obj unless DefineProp is called.

Error Handling

A PropertyError is thrown if Obj does not own a property by that name. The script can determine whether a property is dynamic by checking not desc.HasProp("Value"), where desc is the return value of GetOwnPropDesc.

HasOwnProp

Returns 1 (true) if an object owns a property by the specified name, otherwise 0 (false).

HasOwnProp := Obj.HasOwnProp(Name)

The default implementation of this method is also defined as a function: ObjHasOwnProp(Obj, Name).

OwnProps

Enumerates an object's own properties.

For Name , Value in Obj.OwnProps()

This method returns a new enumerator. The enumerator is typically passed directly to a for-loop, which calls the enumerator once for each iteration of the loop. Each call to the enumerator returns the next property name and/or value. The for-loop's variables correspond to the enumerator's parameters, which are:

Name

Type: String

The property's name.

Value

Type: Any

The property's value.

If the property has a getter method, it is called to obtain the value (unless Value is omitted).

Dynamic properties are included in the enumeration. However:

• Since only the object's own properties are enumerated, the property must be defined directly in Obj.
• If only the first variable was specified, the property's name is returned and its getter is not called.
• If two variables were specified, the enumerator attempts to call the property's getter to retrieve the value.
  • If the getter requires parameters, the property is skipped.
  • If Obj itself does not define a getter for this property, it is skipped.

    Note: Properties defined by a method definition typically do not have a getter, so are skipped.

  • If Obj is a class prototype object, the getter should not (and in some cases cannot) be called; so the property is skipped.
  • If the getter throws an exception, it is propagated (not suppressed). The caller can continue enumeration at the next property only if it retained a reference to the enumerator (i.e. not if it passed the enumerator directly to a for-loop, since in that case the enumerator is freed when the for-loop aborts).

To enumerate own properties without calling property getters, or to enumerate all properties regardless of type, pass only a single variable to the for-loop or enumerator. GetOwnPropDesc can be used to differentiate value properties from dynamic properties, while also retrieving the value or getter/setter/method.

Methods are typically excluded from enumeration in the two-parameter mode, because evaluation of the property normally depends on whether the object has a corresponding getter or value, either in the same object or a base object. To avoid inconsistency when two variables are specified, OwnProps skips over own properties that have only a Call accessor function. For example:

• If OwnProps returned the method itself when no getter is defined, defining a getter would then prevent the method from being returned. Scripts relying on the two variable mode to retrieve methods would then miss some methods.
• If OwnProps returned the method itself when a getter is defined by a base object, this would be inconsistent with normal evaluation of the property.

The default implementation of this method is also defined as a function: ObjOwnProps(Obj).

Base

Retrieves or sets an object's base object.

CurrentBaseObj := Obj.Base

Obj.Base := NewBaseObj

NewBaseObj must be an Object.

If assigning the new base would change the native type of the object, an exception is thrown. An object's native type is decided by the nearest prototype object belonging to a built-in class, such as Object.Prototype or Array.Prototype. For example, an instance of Array must always derive from Array.Prototype, either directly or indirectly.

Properties and methods are inherited from the base object dynamically, so changing an object's base also changes which inherited properties and methods are available.

This property is inherited from Any; however, it can be set only for instances of Object.

See also: ObjGetBase, ObjSetBase

ObjSetBase(Obj, BaseObj)

Count := ObjOwnPropCount(Obj)

MaxProps := ObjSetCapacity(Obj, MaxProps)

MaxItems := ObjGetCapacity(Obj)