# class OptionParser::Switch

Individual switch class. Not important to the user.

Defined within `Switch` are several Switch-derived classes: `NoArgument`, `RequiredArgument`, etc.

### Attributes

arg[R]
block[R]
conv[R]
desc[R]
long[R]
pattern[R]
short[R]

### Public Class Methods

guess(arg) click to toggle source

Guesses argument style from `arg`. Returns corresponding `OptionParser::Switch` class (OptionalArgument, etc.).

    # File lib/optparse.rb, line 511
    def self.guess(arg)
      case arg
      when ""
        t = self
      when /\A=?\[/
        t = Switch::OptionalArgument
      when /\A\s+\[/
        t = Switch::PlacedArgument
      else
        t = Switch::RequiredArgument
      end
      self >= t or incompatible_argument_styles(arg, t)
      t
    end

incompatible_argument_styles(arg, t) click to toggle source

    # File lib/optparse.rb, line 526
    def self.incompatible_argument_styles(arg, t)
      raise(ArgumentError, "#{arg}: incompatible argument styles\n  #{self}, #{t}",
            ParseError.filter_backtrace(caller(2)))
    end

new(pattern = nil, conv = nil, short = nil, long = nil, arg = nil, desc = ([] if short or long), block = nil, &_block) click to toggle source

    # File lib/optparse.rb, line 535
    def initialize(pattern = nil, conv = nil,
                   short = nil, long = nil, arg = nil,
                   desc = ([] if short or long), block = nil, &_block)
      raise if Array === pattern
      block ||= _block
      @pattern, @conv, @short, @long, @arg, @desc, @block =
        pattern, conv, short, long, arg, desc, block
    end

pattern() click to toggle source

    # File lib/optparse.rb, line 531
    def self.pattern
      NilClass
    end

### Public Instance Methods

summarize(sdone = [], ldone = [], width = 1, max = width - 1, indent = "") { |indent| ... } click to toggle source

Produces the summary text. Each line of the summary is yielded to the block (without newline).

`sdone`

  Already summarized short style options keyed hash.

`ldone`

  Already summarized long style options keyed hash.

`width`

  Width of left side (option part). In other words, the right side (description part) starts after `width` columns.

`max`

  Maximum width of left side -> the options are filled within `max` columns.

`indent`

  Prefix string indents all summarized lines.

    # File lib/optparse.rb, line 595
    def summarize(sdone = [], ldone = [], width = 1, max = width - 1, indent = "")
      sopts, lopts = [], [], nil
      @short.each {|s| sdone.fetch(s) {sopts << s}; sdone[s] = true} if @short
      @long.each {|s| ldone.fetch(s) {lopts << s}; ldone[s] = true} if @long
      return if sopts.empty? and lopts.empty? # completely hidden

      left = [sopts.join(', ')]
      right = desc.dup

      while s = lopts.shift
        l = left[-1].length + s.length
        l += arg.length if left.size == 1 && arg
        l < max or sopts.empty? or left << +''
        left[-1] << (left[-1].empty? ? ' ' * 4 : ', ') << s
      end

      if arg
        left[0] << (left[1] ? arg.sub(/\A(\[?)=/, '\1') + ',' : arg)
      end
      mlen = left.collect {|ss| ss.length}.max.to_i
      while mlen > width and l = left.shift
        mlen = left.collect {|ss| ss.length}.max.to_i if l.length == mlen
        if l.length < width and (r = right[0]) and !r.empty?
          l = l.to_s.ljust(width) + ' ' + r
          right.shift
        end
        yield(indent + l)
      end

      while begin l = left.shift; r = right.shift; l or r end
        l = l.to_s.ljust(width) + ' ' + r if r and !r.empty?
        yield(indent + l)
      end

      self
    end

switch_name() click to toggle source

Main name of the switch.

    # File lib/optparse.rb, line 647
    def switch_name
      (long.first || short.first).sub(/\A-+(?:\[no-\])?/, '')
    end

### Private Instance Methods

conv_arg(arg, val = []) click to toggle source

Parses argument, converts and returns `arg`, `block` and result of conversion. Yields at semi-error condition instead of raising an exception.

    # File lib/optparse.rb, line 573
    def conv_arg(arg, val = [])
      if conv
        val = conv.call(*val)
      else
        val = proc {|v| v}.call(*val)
      end
      return arg, block, val
    end

parse_arg(arg) { |InvalidArgument, arg| ... } click to toggle source

Parses `arg` and returns rest of `arg` and matched portion to the argument pattern. Yields when the pattern doesn't match substring.

    # File lib/optparse.rb, line 548
    def parse_arg(arg)
      pattern or return nil, [arg]
      unless m = pattern.match(arg)
        yield(InvalidArgument, arg)
        return arg, []
      end
      if String === m
        m = [s = m]
      else
        m = m.to_a
        s = m[0]
        return nil, m unless String === s
      end
      raise InvalidArgument, arg unless arg.rindex(s, 0)
      return nil, m if s.length == arg.length
      yield(InvalidArgument, arg) # didn't match whole arg
      return arg[s.length..-1], m
    end