Class: OptparseExample

Inherits:
Object
  • Object
show all
Defined in:
lib/sm_transcript/optparseExample.rb

Constant Summary collapse

CODES = 
%w[iso-2022-jp shift_jis euc-jp utf8 binary]
CODE_ALIASES = 
{ "jis" => "iso-2022-jp", "sjis" => "shift_jis" }

Class Method Summary collapse

Class Method Details

.parse(args) ⇒ Object

Return a structure describing the options.



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# File 'lib/sm_transcript/optparseExample.rb', line 17

def self.parse(args)
  # The options specified on the command line will be collected in *options*.
  # We set default values here.
  options = OpenStruct.new
  options.library = []
  options.inplace = false
  options.encoding = "utf8"
  options.transfer_type = :auto
  options.verbose = false

  opts = OptionParser.new do |opts|
    opts.banner = "Usage: example.rb [options]"

    opts.separator ""
    opts.separator "Specific options:"

    # Mandatory argument.
    opts.on("-r", "--require LIBRARY",
            "Require the LIBRARY before executing your script") do |lib|
      options.library << lib
    end

    # Optional argument; multi-line description.
    opts.on("-i", "--inplace [EXTENSION]",
            "Edit ARGV files in place",
            "  (make backup if EXTENSION supplied)") do |ext|
      options.inplace = true
      options.extension = ext || ''
      options.extension.sub!(/\A\.?(?=.)/, ".")  # Ensure extension begins with dot.
    end

    # Cast 'delay' argument to a Float.
    opts.on("--delay N", Float, "Delay N seconds before executing") do |n|
      options.delay = n
    end

    # Cast 'time' argument to a Time object.
    opts.on("-t", "--time [TIME]", Time, "Begin execution at given time") do |time|
      options.time = time
    end

    # Cast to octal integer.
    opts.on("-F", "--irs [OCTAL]", OptionParser::OctalInteger,
            "Specify record separator (default \\0)") do |rs|
      options.record_separator = rs
    end

    # List of arguments.
    opts.on("--list x,y,z", Array, "Example 'list' of arguments") do |list|
      options.list = list
    end

    # Keyword completion.  We are specifying a specific set of arguments (CODES
    # and CODE_ALIASES - notice the latter is a Hash), and the user may provide
    # the shortest unambiguous text.
    code_list = (CODE_ALIASES.keys + CODES).join(',')
    opts.on("--code CODE", CODES, CODE_ALIASES, "Select encoding",
            "  (#{code_list})") do |encoding|
      options.encoding = encoding
    end

    # Optional argument with keyword completion.
    opts.on("--type [TYPE]", [:text, :binary, :auto],
            "Select transfer type (text, binary, auto)") do |t|
      options.transfer_type = t
    end

    # Boolean switch.
    opts.on("-v", "--[no-]verbose", "Run verbosely") do |v|
      options.verbose = v
    end

    opts.separator ""
    opts.separator "Common options:"

    # No argument, shows at tail.  This will print an options summary.
    # Try it and see!
    opts.on_tail("-h", "--help", "Show this message") do
      puts opts
      exit
    end

    # Another typical switch to print the version.
    opts.on_tail("--version", "Show version") do
      puts OptionParser::Version.join('.')
      exit
    end
  end

  opts.parse!(args)
  options
end