R.oo (version 1.22.0)

setConstructorS3: Defines a class in S3/UseMethod style

Description

Defines a class in R.oo/S3 style. What this function currently does is simply creating a constructor function for the class.

Usage

# S3 method for default
setConstructorS3(name, definition, private=FALSE, protected=FALSE, export=TRUE,
  static=FALSE, abstract=FALSE, trial=FALSE, deprecated=FALSE, envir=parent.frame(),
  enforceRCC=TRUE, ...)

A constructor must be callable without arguments

The requirement that a constructor function should be callable without arguments (e.g. MyConstructor()) is because that call is used to create the static instance of a class. The reason for this is that a static instance of the class is created automatically when the constructor is called the first time (only), that is, when the first of object of that class is created. All classes have to have a static instance.

To make a constructor callable without arguments, one can either make sure all arguments have default values or one can test for missing arguments using missing(). For instance the following defintion is not correct: setConstructorS3("Foo", function(x) extend(Object(), "Foo", x=x)) whereas this one is setConstructorS3("Foo", function(x=NA) extend(Object(), "Foo", x=x))

Code validation

If argument enforceRCC is TRUE, the class name is validated so it starts with a letter and it also gives a warning if its first letter is not captial. The reason for this is to enforce a naming convention that names classes with upper-case initial letters and methods with lower-case initial letters (this is also the case in for instance Java).

See Also

To define a method see setMethodS3. For information about the R Coding Conventions, see RccViolationException. For a thorough example of how to use this method see Object.

Examples

# NOT RUN {
For a complete example see help(Object).
# }

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