Allow for family of functions to be identified

[RobertASmith]

Nathan Green at UCL is developing the rocletCHEERs package which allows users to reference specific CHEERS checklist items in Roxygen code for functions. This would mean for example that a function that relates to discounting of costs and benefits would have: @cheers discounting in the roxygen2 code. The benefit of this is having a summary of which functions relate to each item on the checklist.

We want to utilize this functionality in our table, adding the cheers checklist from these tags as a column. For example:

function_name	package	test_path	cheers_item
x	y	z	w

The problem is that we currently identify functions at the function call, not the function definition. Therefore we would need an algorithm to do one of the following:

1. for each function, search for the function definition, which will always start with function_name <- function( or function_name = function(. Look at the roxygen code for the function and locate @cheers and then take the remaining words on that line.

2. just search the code-base for @cheers and each time this string appears identify the function below it. For example in the below we would want to return a list where the element uncertainty contains the function name example_foo.

#' Example Function
#'
#' Description
#'
#' @param param1 Description of Param 1
#' @param param2 Description of Param 2
#' @param param3 Description of Param 3
#'
#' @cheers uncertainty
#'
#' @return what it returns
#'
#' @examples
#' \dontrun{
#'  example_foo()
#' }
#'
example_foo <- function(param1, param2, param3) {
  
<some code>

}