In R, how to print values of fields in a ReferenceClass?

Question

I have a ReferenceClass in R.

How can I add a method "print()" to it, which will print the values of all of the fields in the class?

Answer 1

Perhaps a better implementation is the following

Config = setRefClass("Config",
  fields = list(    
    ConfigBool = "logical", 
    ConfigString = "character"),
  methods = list(
    ## Allow ... and callSuper for proper initialization by subclasses
    initialize = function(...) {
        callSuper(..., ConfigBool=TRUE, ConfigString="A configuration string")
        ## alterantive:
        ##    callSuper(...)
        ##    initFields(ConfigBool=TRUE, ConfigString="A configuration string")
    },
    ## Implement 'show' method for automatic display
    show = function() {
        flds <- getRefClass()$fields()
        cat("* Fields\n")
        for (fld in names(flds))  # iterate over flds, rather than index of flds
            cat('  ', fld,': ', .self[[fld]], '\n', sep="")
    })
  )

The following illustrates use of the Config constructor (no need to invoke 'new') and automatic invocation of 'show'

> Config()
* Fields
  ConfigBool: TRUE
  ConfigString: A configuration string