fn_body {rlang}

Get or set function body

Description

fn_body() is a simple wrapper around base::body(). It always returns a ⁠\{⁠ expression and throws an error when the input is a primitive function (whereas body() returns NULL). The setter version preserves attributes, unlike ⁠body<-⁠.

Usage

fn_body(fn = caller_fn())

fn_body(fn) <- value

Arguments

fn

A function. It is looked up in the calling frame if not supplied.

value

New formals or formals names for fn.

Examples

# fn_body() is like body() but always returns a block:
fn <- function() do()
body(fn)
fn_body(fn)

# It also throws an error when used on a primitive function:
try(fn_body(base::list))