Robert Klemme
2/4/2007 10:22:00 PM
On 04.02.2007 22:49, Thai Le wrote:
> I've done java for a few years and ruby is pretty new to me. In java, a
> method has visibility(private, protected, public) and
Actually there are four of them: you have to add "package" visibility to
the list. :-)
> accessibility(static, non-static); however, in ruby how can I declare
> the method: "public static method1"? It seem that the default visibility
> of a method is public in ruby, am i correct?
Yes. Strictly speaking there are no static methods in Ruby. But it has
the concept of singleton methods that are defined for a single instance
only. And since classes are just ordinary objects you can define
instance methods of class objects and achieve basically the same as with
Java's static methods:
class Foo
def self.a_class_method
# ...
end
def an_instance_method
self.class.a_class_method
self.another_class_method
end
end
def Foo.another_class_method
# ...
end
> One morething is that java program starts from "public static main()".
> What is the entry point to ruby program?
The situation is a bit different because Ruby is interpreted. If you
want, you can view the root script you invoke as the body of main, i.e.,
code is executed top down. However, part of this execution are class,
method and constant definitions. Invocation arguments are accessible
via ARGV (and also ARGF which is a special shortcut which will read from
all files in ARGV). So, strictly speaking there is no equivalent of
Java's and C's "main" but the functionality is there.
Kind regards
robert