Inspecting Option Values

Usage

opt(x, default, env = parent.frame())

opt_source(x, env = parent.frame())

opts(xs = NULL, env = parent.frame())

Arguments

x, xs: An option name or vector of option names
default: A default value if the option is not set
env: An environment, namespace or package name to pull options from

Value

For opt() and opts(); the result of the option (or a list of results), either the value from a global option, the result of processing the environment variable or the default value, depending on which of the alternative sources are defined.

For opt_source(); the source that is used for a specific option, one of "option", "envir" or "default".

Functions

opt(): Retrieve an option
opt_source(): Determine source of option value. Primarily used for diagnosing options behaviors.
opts(): Retrieve multiple options. When no names are provided, return a list containing all options from a given environment.

Examples

define_options("Whether execution should emit console output", quiet = FALSE)
#> 
#> quiet = FALSE
#> 
#>   Whether execution should emit console output
#> 
#>   option  : globalenv.quiet
#>   envvar  : R_GLOBALENV_QUIET (evaluated if possible, raw string otherwise)
#>  *default : FALSE
#> 
opt("quiet")
#> [1] FALSE

define_options("Whether execution should emit console output", quiet = FALSE)
#> 
#> quiet = FALSE
#> 
#>   Whether execution should emit console output
#> 
#>   option  : globalenv.quiet
#>   envvar  : R_GLOBALENV_QUIET (evaluated if possible, raw string otherwise)
#>  *default : FALSE
#> 
opt_source("quiet")
#> [1] "default"

Sys.setenv(R_GLOBALENV_QUIET = TRUE)
opt_source("quiet")
#> [1] "envir"

options(globalenv.quiet = FALSE)
opt_source("quiet")
#> [1] "option"