metaprogramming example from http://goo.gl/fmIh4T

metaprogramming.r

# script from http://goo.gl/fmIh4T

myFun <- function(vec) {
  numElements <- length(which(vec > threshold))
  numElements
}

genMyFuns <- function(thresholds) {
  ll <- length(thresholds)
  print("Generating functions:")
  for(i in 1:ll) {
    fName <- paste("myFun.", i, sep="")
    print(fName)
    assign(fName, eval(
                       substitute(
                                  function(vec) {
                                    numElements <- length(which(vec > tt));
                                    numElements;
                                  }, 
                                  list(tt=thresholds[i])
                                 )
                      ),
             envir=parent.frame()
           )
  }
}

genMyFuns(c(7, 9, 10))
myFun.1(1:20)
myFun.2(1:20)
myFun.3(1:20)