setProxyClass {XR}

Create a Proxy Class

Description

Creates a proxy class of a given name and other requirements. Usually infers fields and methods from server language metadata, but can also use explicitly supplied values. Particular interface packages will typically have a specialized version that calls this function.

Usage

setProxyClass(Class, module = "", fields = character(), methods = NULL,
  ServerClass = Class, where = topenv(parent.frame()),
  contains = character(), evaluatorClass,
  proxyObjectClass = "ProxyClassObject", language = if (is.null(evaluator))
  "" else evaluator$languageName, readOnly = NULL, ..., save = FALSE,
  objName = Class, docText = NULL)

Arguments

Class

the name of the class to be used in the proxy, usually just the server language class.

module

the name of the server langauge module if it needs to be imported.

fields, methods

explicit field and method information if this cannot be found by inspection. Normally omitted.

ServerClass

the name of the server language class, normall defaults to Class.

where

the environment for the class definition. By default, and nearly always, the namespace of the package in which the call to setProxyClass() occurs.

contains

explicitly needed superclasses if any.

evaluatorClass

the evaluator class to identify the evaluator, e.g. "PythonInterface" for Python. By default, the current evaluator class.

proxyObjectClass

The general class for proxy objects in this interface. Typically obtained automatically from the prototypObject field of the evaluator.

language

the server language, taken from the evaluator if one is found.

readOnly

character vector of any field names that should be marked read-only.

...

extra arguments to pass on to setRefClass().

save

If the proxy class is being defined in an application package, use this to write to a source file (see Ch. 12 of Extending R) Default FALSE, if the proxy class is being assigned in the installation or load of a package.

objName

When using the save= argument to write R code, use this name in the assignment expression for the generator object. By default, the name of the class.

docText

metadata information supplied by the interface for a particular server language.

Details

A proxy class has fields and methods that are created to use the corresponding fields and methods of the server language, through an interface evaluator. This function normally expects information about the class to be returned by the $ServerClassDef() method of the evaluator, specialized to the language. It can also be called with explicit lists for the fields and methods. The actual fields and methods will use the interface to access or call the corresponding code in the server language.

Value

a generator object for the R class, along with the side effect of setting the class definition.

References

Chambers, John M. (2016) Extending R, Chapman & Hall/CRC. ( Chapter 13, discussing this package, is included in the package: ../doc/Chapter_XR.pdf.)