passing and returning a variable to a function in r

Question

I created a function and want to replace x by another variable called s and set y=3. How to do it so that the function with return s+3?

myfun <- function(x, y){ x + y }

myfun(s, 3) will give me an error that s is undefined. 

Answer 1

It sounds like you just want the substitute function

myfun <- function(x, y){ substitute(x + y) }
myfun(s, 3)
# s + 3