Change global options
local_options() changes options for the duration of a stack
frame (by default the current one). Options are set back to their
old values when the frame returns.
with_options() changes options while an expression is
evaluated. Options are restored when the expression returns.
push_options() adds or changes options permanently.
peek_option() and peek_options() return option values. The
former returns the option directly while the latter returns a
list.
local_options(..., .frame = caller_env()) with_options(.expr, ...) push_options(...) peek_options(...) peek_option(name)
... |
For |
.frame |
The environment of a stack frame which defines the scope of the temporary options. When the frame returns, the options are set back to their original values. |
.expr |
An expression to evaluate with temporary options. |
name |
An option name as string. |
For local_options() and push_options(), the old option
values. peek_option() returns the current value of an option
while the plural peek_options() returns a list of current
option values.
These functions are experimental.
# Store and retrieve a global option:
push_options(my_option = 10)
peek_option("my_option")
# Change the option temporarily:
with_options(my_option = 100, peek_option("my_option"))
peek_option("my_option")
# The scoped variant is useful within functions:
fn <- function() {
local_options(my_option = 100)
peek_option("my_option")
}
fn()
peek_option("my_option")
# The plural peek returns a named list:
peek_options("my_option")
peek_options("my_option", "digits")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.