module Argos

Constants

VERSION

Public Instance Methods

argument_missing(opt) click to toggle source

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

   # File lib/argos.rb
12 def argument_missing opt
13   raise OptionError, "#{opt}: no argument provided."
14 end
handle(opt, handler, *args) click to toggle source 
   # File lib/argos.rb
16 def handle opt, handler, *args # :nodoc
17   args.empty? ?  handler[] : handler[args[0]]
18 rescue => ex
19   raise OptionError, "#{opt}: #{ex}"
20 end
parse_options(argv, optdef) click to toggle source

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.

   # File lib/argos.rb
51 def parse_options argv, optdef
52   orig = argv.dup; argv.clear
53   opts = {}
54 
55   loop do
56     case (argstr=orig.shift)
57     when nil, "--"
58       argv.concat orig
59       break
60 
61     when /^(--)([^=]+)=(.*)/, /^(-)([^-])(.+)/
62       short = ($1 == "-"); opt = $2; arg = $3
63       unless optdef.key?(opt)
64         argv << argstr
65         next
66       end
67       handler = optdef[opt]
68       arity = (handler.arity rescue nil)
69       opts[opt] =
70         case arity
71         when nil;   orig.unshift("-#{arg}") if short; handler
72         when 0,-1;  orig.unshift("-#{arg}") if short; handle(opt, handler)
73         else        handle(opt, handler, arg)
74         end
75 
76     when /^--(.+)/, /^-(.)$/
77       opt = $1
78       unless optdef.key?(opt)
79         argv << argstr
80         next
81       end
82       handler = optdef[opt]
83       arity = (handler.arity rescue nil)
84       opts[opt] =
85         case arity
86         when nil;   handler
87         when 0,-1;  handle(opt, handler)
88         else        handle(opt, handler, orig.shift || argument_missing(opt))
89         end
90 
91     else
92       argv << argstr
93     end
94   end
95 
96   opts
97 end