# wrap a function into a command object
register <- function(name, operation) {
  proto(
    name = name,
    func = operation,
    perform = function(., ...) {
      func <- with(., func) # unwrap bound proto method
      do.call(func, list(), envir=environment(operation))
    }
    )
}

# dynamic invocation test outside of proto
do_call_test <- function(operation) {
  do.call(operation, list(), envir=environment(operation))
}

context('proto with functions as data')

test_that("cmd execution", {

  # This varible should be visible inside op
  command_result <- 100

  op <- function() {

    # Utility to list all variables in an environment
    # Modified from Matloff, Norman. The Art of R Programming
    show.frame <- function(upn) {
      # determine the proper environment
      if (upn < 0) {
        env <- .GlobalEnv
      } else {
        env <- parent.frame(n=upn+1)
      }
      cat('\nShowing frame', upn, 'with the following environment\n')
      print(env)
      cat('Variables:\n')
      # get the list of variable names
      vars <- ls(envir=env)
      # for each variable name, print its value
      for (vr in vars) {
        vrg <- get(vr,envir=env)
        if (!is.function(vrg)) {
          cat(vr,":\n",sep="")
          print(vrg)
        }
      }
    }

    for (n in c(0, 1, 2)) {
      cat("\nFrame", n, "\n")
      show.frame(n)
    }

    command_result
  }

  cat('\n\nCurrent environment\n')
  print(environment())

  cat("\n---- Calling op directly\n")
  expect_equal(op(), command_result)

  cat("\n---- Calling op with do.call\n")
  expect_equal(do_call_test(op), command_result)

  cat("\n---- Calling op with do.call inside proto\n")
  cmd <- register('cmd', op)
  expect_equal(cmd$perform(), command_result)
})