Command-Line Argument Parser.

README

argparser is a cross-platform command-line argument parser for R, written in R, with no external dependencies. This package is useful with the Rscript front-end and facilitates turning an R script into an executable script.

History

v0.7

• Missing argument values are now handled correctly

v0.6

Incompatibility: values of numeric and integer arguments are now checked for validity due to feature request (issue #16)

v0.5.1

• Negative numbers can now be parsed correctly as argument values
• Help message printing is prettier
• Concatenated short-form flags are now split into individual flags

v0.4 Simplify argument names

Incompatibility: - in argument names are substitute by _

v0.3 Added support for multi-valued arguments

v0.2 Function names change

Incompatibility: . in function names are replaced with _

v0.1 Initial release

Dependencies

• R (>= 3.0)
• roxygen2 (>= 4.0, for building only)

Build

Clone the repository, build the documentation with roxygen2, then install.

$ git clone https://bitbucket.org/djhshih/argparser.git
$ cd argparser
$ R

R> library(roxygen2)
R> roxygenize()
R> quit()

$ R CMD INSTALL .

Usage

Create a R script (e.g. round.R) with a shebang line (Linux only).

Import the argparser library, create a parser, populate the parser with arguments and parse the command line arguments.

#!/usr/bin/env Rscript

library(argparser, quietly=TRUE)

# Create a parser
p <- arg_parser("Round a floating point number")

# Add command line arguments
p <- add_argument(p, "number", help="number to round", type="numeric")
p <- add_argument(p, "--digits", help="number of decimal places", default=0)

# Parse the command line arguments
argv <- parse_args(p)

# Do work based on the passed arguments
cat( round(argv$number, argv$digits), "\n")

Then, set the R script as executable and execute (Linux only).

$ chmod +x round.R

# Print the help message
$ ./round.R -h

Alternatively, run the script using Rscript (Linux or Windows).

$ Rscript round.R 3.141
# 3

$ Rscript round.R 3.141 -d 2
# 3.14

For R help, see ?argparser.