setGlobalOptions {GlobalOptions}

Produce a function which can get or set global options

Description

Produce a function which can get or set global options

Usage

setGlobalOptions(...)

Arguments

...

specification of options, see 'details' section

Details

The function has a short name set_opt.

The most simple way is to construct an option function (e.g. opt()) as:

    opt = set_opt(
        "a" = 1,
        "b" = "text"
    )  

Then users can get or set the options by

    opt()
    opt("a")
    opt$a
    opt[["a"]]
    opt(c("a", "b"))
    opt("a", "b")
    opt("a" = 2)
    opt$a = 2
    opt[["a"]] = 2
    opt("a" = 2, "b" = "new_text")  

Options can be reset to their default values by:

    opt(RESET = TRUE)  

The value for each option can be set as a list which contains more configurations of the option:

    opt = set_opt(
        "a" = list(.value = 1,
                   .length = 1,
                   .class = "numeric",
                   .validate = function(x) x > 0)
    )  

The different fields in the list can be used to filter or validate the option values.

.value

The default value.

.length

The valid length of the option value. It can be a vector, the check will be passed if one of the length fits.

.class

The valid class of the option value. It can be a vector, the check will be passed if one of the classes fits.

.validate

Validation function. The input parameter is the option value and should return a single logical value.

.failed_msg

Once validation failed, the error message that is printed.

.filter

Filtering function. The input parameter is the option value and it should return a filtered option value.

.read.only

Logical. The option value can not be modified if it is set to TRUE.

.visible

Logical. Whether the option is visible to users.

.private

Logical. The option value can only be modified in the same namespace where the option function is created.

.synonymous

a single option name which should have been already defined ahead of current option. The option specified will be shared by current option.

.description

a short text for describing the option. The description is only used when printing the object.

For more detailed explanation, please go to the vignette.

Author(s)

Zuguang Gu <[e-mail]>

Examples

opt = set_opt(
    a = 1,
    b = "text"
)
opt
# for more examples, please go to the vignette