From: Mark Wilson <mwilson13@...>
Date: 2003-06-12T05:50:56+09:00
Subject: Re: Multiple Initialize methods?


> On Thu, 12 Jun 2003 04:54:59 +0900, Nick wrote:
>> Hi,
>>
>> I need to create a class either with a param in the construction
>> or nothing:
>>
>>   something = Object.new
>> or
>>   something = Object.new(val1, val2)
>>
>> [snip]

It occurs to me that a standard way to do something like this in Ruby 
is as follows (taken from set.rb):

The code below gives two methods to create the object:

Set.new [returns empty set]

Set.new([_array_]) [returns a set, each element of which is an element 
of the given array (without duplicates)]

Set.new({_hash_}) [returns a set, each element of which is an array 
consisting of the given key-value pairs]

Set[_array_] [returns a set, each element of which is an element of the 
given array (without duplicates)]

Set.[](_elements_) [returns a set, each element of which is one of the 
given elements (without duplicates)]

Code from set.rb:

   # Creates a new set containing the given objects. [Notice the call to 
the 'new' method.]
   def self.[](*ary)
     new(ary)
   end

   # Creates a new set containing the elements of the given enumerable
   # object.
   #
   # If a block is given, the elements of enum are preprocessed by the
   # given block.
   def initialize(enum = nil, &block) # :yields: o
     @hash ||= Hash.new

     enum.nil? and return

     if block
       enum.each { |o| add(block[o]) }
     else
       merge(enum)
     end
   end