opt {arrg} | R Documentation |
Specify an option in long or short form
Description
This function specifies an option that is accepted by an argument parser.
The results of one or more calls to this function are typically passed to
arrg()
.
Usage
opt(label, description, arg = FALSE, default = NA_character_)
Arguments
label |
A short-form (single character) and/or long-form label for the option, specified comma-separated in a single string. At most one of each form must be given. Leading hyphens are optional. |
description |
A textual description of the option, for use in the usage summary. |
arg |
The name of the option's argument, if it takes one. Otherwise
|
default |
A default value for the argument, if one is accepted. This
does not have to be a string, and arguments will be coerced to match the
mode of the default when parsed. If the option takes no argument the
default value will be |
Value
A data frame giving details of the option. This will not usually be
used directly, but passed to arrg()
.
Author(s)
Jon Clayden
See Also
Examples
# A simple flag-style option with no argument
opt("h,help", "Display this usage information and exit")
# An option that takes an integer argument called "count"
opt("n,times", "Run this many times", arg="count", default=1L)