From: ts <decoux@...>
Date: 2002-12-01T02:33:20+09:00
Subject: Re: Ruby Document

>>>>> "S" == Shannon Fang <xrfang@hotmail.com> writes:

S> Can I omit this ::? Is it valid to omit it? or it has a "namespace" impact? 
 yes, it has an impact. For example

pigeon% cat b.rb
#!/usr/bin/ruby
class A; end

p A == ::A, A

module B
   p A == ::A, A

   class A
   end

   p A == ::A, A
end
pigeon% 

pigeon% b.rb
true
A
true
A
false
B::A
pigeon% 

 For the 2 first test, A and ::A make reference to the same class

 In the last test 
   A   make reference to the class B::A
   ::A make reference to the toplevel class A


S> When should I use :: at top level?

 useless at toplevel :-)

S> What is a symbol? what is the difference between symbol and variable?

 a symbol is an Object, like an Integer, Array, ...

pigeon% ruby -e 'p :name.class; p 12.class'
Symbol
Fixnum
pigeon% 


S> It seems HTTP#get is a class method? or if not? what is the symbol # mean, 
S> in method definition?

 This is just a convention

  HTTP#method  is the convention for an instance method
  HTTP::method is the convention for a class method

 For example

   class HTTP
      def HTTP.get(a, b)
      end

      def gets(d)
      end
   end

 HTTP::get is a class method
 HTTP#gets is an instance method


Guy Decoux