Module: Argos

Defined in:
lib/argos.rb

Defined Under Namespace

Classes: OptionError

Constant Summary collapse

VERSION = 
"1.0"

Class Method Summary collapse

Class Method Details

.argument_missing(opt) ⇒ Object

Called when an option that takes an argument occurs at the end of the argv list, with no argument following it.

Raises:



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# File 'lib/argos.rb', line 12

def argument_missing opt
  raise OptionError, "#{opt}: no argument provided."
end

.handle(opt, handler, *args) ⇒ Object

:nodoc



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# File 'lib/argos.rb', line 16

def handle opt, handler, *args # :nodoc
  args.empty? ?  handler[] : handler[args[0]]
rescue => ex
  raise OptionError, "#{opt}: #{ex}"
end

.parse_options(argv, optdef) ⇒ Object

Returns the hash of parsed options and argument values. The argv array is modified: every recognized option and argument is deleted.

The optdef hash defines the options and their arguments.

Each key is an option name (without “-” chars).

The value for a key in optdef is used to generate the value for the same key in the options hash returned by this method.

If the value has an #arity method and arity > 0, the value is considered to be a handler; it is called with the argument string to return the value associated with the option in the hash returned by the method.

If the arity <= 0, the value is considered to be a handler for an option without arguments; it is called with no arguments to return the value of the option.

If there is no arity method, the object itself is used as the value of the option.

Only one kind of input will cause an exception (not counting exceptions raised by handler code or by bugs):

  • An option is found at the end of the list, and it requires an argument. This results in a call to #argument_missing, which by default raises OptionError.



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# File 'lib/argos.rb', line 51

def parse_options argv, optdef
  orig = argv.dup; argv.clear
  opts = {}

  loop do
    case (argstr=orig.shift)
    when nil, "--"
      argv.concat orig
      break

    when /^(--)([^=]+)=(.*)/, /^(-)([^-])(.+)/
      short = ($1 == "-"); opt = $2; arg = $3
      unless optdef.key?(opt)
        argv << argstr
        next
      end
      handler = optdef[opt]
      arity = (handler.arity rescue nil)
      opts[opt] =
        case arity
        when nil;   orig.unshift("-#{arg}") if short; handler
        when 0,-1;  orig.unshift("-#{arg}") if short; handle(opt, handler)
        else        handle(opt, handler, arg)
        end

    when /^--(.+)/, /^-(.)$/
      opt = $1
      unless optdef.key?(opt)
        argv << argstr
        next
      end
      handler = optdef[opt]
      arity = (handler.arity rescue nil)
      opts[opt] =
        case arity
        when nil;   handler
        when 0,-1;  handle(opt, handler)
        else        handle(opt, handler, orig.shift || argument_missing(opt))
        end

    else
      argv << argstr
    end
  end

  opts
end