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Extract a named command-line argument

Source: R/calibrar-auxiliar.R
dot-get_command_argument.Rd

Parse command-line arguments and return the value associated with a named option. This helper is primarily intended for scripting workflows that call R from the shell and pass arguments such as --config=file.txt.

Usage

.get_command_argument(
  x,
  argument,
  prefix = "--",
  default = FALSE,
  verbose = FALSE
)

Arguments

x

Character vector of command-line arguments, typically obtained from commandArgs().

argument

Name of the argument to retrieve, without the prefix.

prefix

Prefix used for arguments of interest. The default is "--".

default

Value returned when the argument is not found. The default is FALSE.

verbose

Logical. If TRUE, a warning is issued when the requested argument is not found.

Value

The parsed argument value. If the argument is present without an explicit =value part, TRUE is returned. If the argument is absent, default is returned. Parsed values are passed through an internal type guesser, so logical and numeric values may be returned with their corresponding R types.

Details

The function looks for entries matching either prefix + argument or prefix + argument = value. For example, with prefix = "--" and argument = "config", both --config and --config=file.txt are recognised.

This function is exported because it can be useful in external packages or scripts that build command-line interfaces around calibrar workflows.

See also

.read_configuration()

Examples

.get_command_argument(commandArgs(), "interactive")
#> [1] FALSE
.get_command_argument(commandArgs(), "RStudio")
#> [1] FALSE
.get_command_argument(commandArgs(), "RStudio", prefix = "")
#> [1] FALSE
.get_command_argument(commandArgs(), "vanilla")
#> [1] FALSE
.get_command_argument("--control.file=baz.txt", "control.file")
#> [1] "baz.txt"