Operator overloading and class definition in R: Use a different base field/corpus

Question

(I\'m using the word \"field\" in the mathematical sense; base fields/corpora which R already uses include the real and complex numbers.)

I\'m intereste

Answer 1

I found Hadley Wickham's devtools wiki an invaluable resource for getting started with classes in R. In particular, read the sections on:

• S3 classes
• S4 classes

Here is a starting point that illustrates some of the concepts in S3 classes. Let's call your new class f5. At a minimum, you would probably want to create methods for:

• Coercion: as.f5
• Test: is.f5
• Some basic operators: +.f5
• A class to handle printing: print.f5

Some code (using digitsBase in package GLDEX to do the base conversion):

library(GLDEX)

as.f5 <- function(x){
  if(!inherits(x, "f5")) class(x) <- c("f5", class(x))
  x
}

is.f5 <- function(x){
  inherits(x, "f5")
}

`+.f5` <- function(e1, e2){
  NextMethod(e1, e2)
}

print.f5 <- function(x, ...){
  # Next line from ?GLDEX::digitsBase
  b2ch <- function(db) noquote(gsub("^0+(.{1,})$"," \1", 
                           apply(db, 2, paste, collapse = "")))

  cat("Base 5:\n")
  cat(b2ch(digitsBase(x, 5)))
  invisible(x)
}


x <- as.f5(0:10)
y <- as.f5(5)

x + y

Base 5:
10 11 12 13 14 20 21 22 23 24 30