RGtk2 (version 2.20.31)

RGtkObject: The base object of RGtk2

Description

RGtkObject identifies an external object as being owned by RGtk. Practically, it allows convenience operators to be specified for any external object.

Usage

"[["(x, field, where = parent.frame())
"$"(x, member)
"=="(x, y)

Arguments

x

The RGtkObject to which the method or field belongs or the left hand of a comparison

field

The name of the field whose value will be retrieved

member

The name of the member (eg method) that will be retrieved

y

The right hand operand of a comparison

where

The environment in which to look for the field accessor function

Value

A context-dependent value resulting from the specified API call.

Details

The functions [[.RGtkObject and $.RGtkObject both expand to an RGtk function that accesses external objects. The [[ operator looks for a field from an external C structure by expanding objectOfClassName[[fieldName]] to classNameGetFieldName(). External "methods" are expanded by the $ operator to form classNameMethodName(objectOfClassName, ...) from the Java-like objectOfClassName$methodName(...). The long and short mechanisms give the same result, but the shortcut is obviously more convenient. If the method does not exist, $ will fall back to other types of members, like properties (for GObjects) and fields.

The == operator compares two RGtkObjects on the basis of their internal pointer value. This should rarely be useful for users.