Closure environments define the scope of functions (see env()).
When a function call is evaluated, R creates an evaluation frame
(see ctxt_stack()) that inherits from the closure environment.
This makes all objects defined in the closure environment and all
its parents available to code executed within the function.
fn_env(fn) fn_env(x) <- value
| fn, x | A function. |
|---|---|
| value | A new closure environment for the function. |
fn_env() returns the closure environment of fn. There is also
an assignment method to set a new closure environment.
env <- child_env("base") fn <- with_env(env, function() NULL) identical(fn_env(fn), env) #> [1] TRUE other_env <- child_env("base") fn_env(fn) <- other_env identical(fn_env(fn), other_env) #> [1] TRUE