Trollop

Informs the user that their usage of 'arg' was wrong, as detailed by 'msg', and dies. Example:

options do
  opt :volume, :default => 0.0
end

die :volume, "too loud" if opts[:volume] > 10.0
die :volume, "too soft" if opts[:volume] < 0.1

In the one-argument case, simply print that message, a notice about -h, and die. Example:

options do
  opt :whatever # ...
end

Trollop::die "need at least one filename" if ARGV.empty?

# File lib/trollop.rb, line 727
def die arg, msg=nil
  if msg
    $stderr.puts "Error: argument --#{@p.specs[arg][:long]} #{msg}."
  else
    $stderr.puts "Error: #{arg}."
  end
  $stderr.puts "Try --help for help."
  exit(-1)
end

The top-level entry method into Trollop. Creates a Parser object, passes the block to it, then parses args with it, handling any errors or requests for help or version information appropriately (and then exiting). Modifies args in place. Returns a hash of option values.

The block passed in should contain zero or more calls to opt (Parser#opt), zero or more calls to text (Parser#text), and probably a call to version (Parser#version).

The returned block contains a value for every option specified with opt. The value will be the value given on the commandline, or the default value if the option was not specified on the commandline. For every option specified on the commandline, a key "<option name>_given" will also be set in the hash.

Example:

require 'trollop'
opts = Trollop::options do
  opt :monkey, "Use monkey mode"                     # a flag --monkey, defaulting to false
  opt :goat, "Use goat mode", :default => true       # a flag --goat, defaulting to true
  opt :num_limbs, "Number of limbs", :default => 4   # an integer --num-limbs <i>, defaulting to 4
  opt :num_thumbs, "Number of thumbs", :type => :int # an integer --num-thumbs <i>, defaulting to nil
end

## if called with no arguments
p opts # => { :monkey => false, :goat => true, :num_limbs => 4, :num_thumbs => nil }

## if called with --monkey
p opts # => {:monkey_given=>true, :monkey=>true, :goat=>true, :num_limbs=>4, :help=>false, :num_thumbs=>nil}

See more examples at trollop.rubyforge.org.

# File lib/trollop.rb, line 689
def options args = ARGV, *a, &b
  @p = Parser.new(*a, &b)
  begin
    vals = @p.parse args
    args.clear
    @p.leftovers.each { |l| args << l }
    vals
  rescue CommandlineError => e
    $stderr.puts "Error: #{e.message}."
    $stderr.puts "Try --help for help."
    exit(-1)
  rescue HelpNeeded
    @p.educate
    exit
  rescue VersionNeeded
    puts @p.version
    exit
  end
end