rlang (version 0.2.1)

new_function: Create a function

Description

This constructs a new function given it's three components: list of arguments, body code and parent environment.

Usage

new_function(args, body, env = caller_env())

Arguments

args

A named list of default arguments. Note that if you want arguments that don't have defaults, you'll need to use the special function alist, e.g. alist(a = , b = 1)

body

A language object representing the code inside the function. Usually this will be most easily generated with base::quote()

env

The parent environment of the function, defaults to the calling environment of new_function()

Examples

# NOT RUN {
f <- function(x) x + 3
g <- new_function(alist(x = ), quote(x + 3))

# The components of the functions are identical
identical(formals(f), formals(g))
identical(body(f), body(g))
identical(environment(f), environment(g))

# But the functions are not identical because f has src code reference
identical(f, g)

attr(f, "srcref") <- NULL
# Now they are:
stopifnot(identical(f, g))
# }