Parse command-line arguments

Parse command-line arguments is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Command-line arguments can be quite complicated, as in "nc -v -n -z -w 1 192.168.1.2 1-1000". Many languages provide a library (getopt or GetOpt) to parse the raw command line options in an intelligent way.

Icon and Unicon

The Icon Programming Library provides a procedure for processing command line options. See the library reference for detailed documentation. The code below is an example.

<lang Icon>link options

procedure main(ARGLIST) /errproc := stop # special error procedure or stop() opstring := "f!s:i+r.flag!string:integer+real." # example opttable := options(ARGLIST,optstring,errproc)

if \opttable[flag] then ... # test a flag r  := opttable(real) # assign a real r2 := opttable(r) # assign another real s  := opttable(s) # assign a string i  := opttable(i) # assign an integer ... end</lang>

Library: Icon Programming Library

options.icn supports getting command-line options

Ruby

<lang shell>$ ./pargs.rb -h

Usage

---

pargs [OPTIONS]

--help, -h:

  show usage

--eddy, -e <message>

  call eddy

--daniel, -d <message>

  call daniel

--test, -t

  run unit tests

$ ./pargs.rb -e Yo! Calling eddy... Yo! $ ./pargs.rb --test Calling Barry... Hi! Calling Cindy... Hello!</lang>

<lang ruby>#!/usr/bin/env ruby

1. == Synopsis
3. pargs: Phone a friend
5. == Usage
7. pargs [OPTIONS]
9. --help, -h:
10. show usage
12. --eddy, -e <message>
13. call eddy
15. --danial, -d <message>
16. call daniel
18. --test, -t
19. run unit tests

require "getoptlong" require "rdoc/usage"

def phone(name, message) puts "Calling #{name}..." puts message end

def test phone("Barry", "Hi!") phone("Cindy", "Hello!") end

def main mode = :usage

name = "" message = ""

opts=GetoptLong.new( ["--help", "-h", GetoptLong::NO_ARGUMENT], ["--eddy", "-e", GetoptLong::REQUIRED_ARGUMENT], ["--daniel", "-d", GetoptLong::REQUIRED_ARGUMENT], ["--test", "-t", GetoptLong::NO_ARGUMENT] )

opts.each { |option, value| case option when "--help" RDoc::usage("Usage") when "--eddy" mode = :call name = "eddy" message = value when "--daniel" mode = :call name = "daniel" message = value when "--test" mode = :test end }

case mode when :usage RDoc::usage("Usage") when :call phone(name, message) when :test test end end

if __FILE__==$0 begin main rescue Interrupt => e nil end end</lang>