R - Converting a Function to String -

i working on function behave similar reduce pass in function , dispatch on arguments. here simple example demonstrate working on.

fun <- function(f){      switch(f,            `+` = "addition",            stop("undefined")     ) }  fun(`+`) 

now won't work stands because switch requires character or numeric expr. don't know how convert function f passed fun string.

one approach capture input , deparse call.

fun <- function(f){   switch(deparse(substitute(f)),          `+` = "addition",          stop("undefined")   ) }  fun(`+`) #[1] "addition"