Class: Getopt::Std

Inherits:
Object
  • Object
show all
Includes:
Version
Defined in:
lib/getopt/std.rb

Overview

The Getopt::Std class serves as a base class for the getopts method.

Defined Under Namespace

Classes: Error

Constant Summary

Constants included from Version

Version::VERSION

Class Method Summary collapse

Class Method Details

.getopts(switches) ⇒ Object

Processes single character command line options with option clustering. This information is parsed from ARGV and returned as a hash, with the switch (minus the “-”) as the key. The value for that key is either true/false (boolean switches) or the argument that was passed to the switch.

Characters followed by a “:” require an argument. The rest are considered boolean switches. If a switch that accepts an argument appears more than once, the value for that key becomes an array of values.

Example:

# Look for -o with argument, and -I and -D boolean arguments
opt = Getopt::Std.getopts("o:ID")

if opt["I"]
  # Do something if -I passed
end

if opt["D"]
   # Do something if -D passed
end

if opt["o"]
   case opt["o"]
      # Do something
   end
end



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# File 'lib/getopt/std.rb', line 45

def self.getopts(switches)
   args = switches.split(/ */)
   hash = {}

   while !ARGV.empty? && ARGV.first =~ /^-(.)(.*)/s
      first, rest = $1, $2
      pos = switches.index(first)

      # Switches on the command line must appear among the characters
      # declared in +switches+.
      raise Error, "invalid option '#{first}'" unless pos

      if args[pos+1] == ":"
         ARGV.shift
         if rest.empty?
            rest = ARGV.shift

            # Ensure that switches requiring arguments actually
            # receive a (non-switch) argument.
            if rest.nil? || rest.empty?
               raise Error, "missing argument for '-#{args[pos]}'"
            end

            # Do not permit switches that require arguments to be
            # followed immediately by another switch.
            temp_args = args.map{ |e| "-#{e}" }

            if temp_args.include?(rest) || temp_args.include?(rest[1..-1])
               err = "cannot use switch '#{rest}' as argument "
               err << "to another switch"
               raise Error, err
            end

            # For non boolean switches, arguments that appear multiple
            # times are converted to an array (or pushed onto an already
            # existant array).
            if hash.has_key?(first)
               hash[first] = [hash[first], rest].flatten
            else
               hash[first] = rest
            end
         else
            # Do not permit switches that require arguments to be
            # followed immediately by another switch.
            if args.include?(rest) || args.include?(rest[1..-1])
               err = "cannot use switch '#{rest}' as argument "
               err += "to another switch"
               raise Error, err
            end
         end
      else
         hash[first] = true # Boolean switch
         if rest.empty?
            ARGV.shift
         else
            ARGV[0] = "-#{rest}"
         end
      end
   end

   hash
end