C++ namespaces in Ruby

ruby-talk
1

Recently someone pointed out that in his opinion there was just one thing
Ruby was missing, which was something like C++ namespaces. Someone else
replied that in that case the OP should use Ruby modules. That’s not
exactly true, IMO. In C++ the most significant difference between
namespaces and classes is that namespaces are open, and classes are shut.
Meaning that you can always add things to an already defined namespace, but
you can not add anything to an existing class (unless you happen to have the
source code of that class). In contrast, Ruby classes are always open, you
can always add things to them, etc. , so in that way Ruby classes are like
C++ namespaces. IMO if you want to achieve C+±like namespaces in Ruby,
you’d be best off by using a Ruby class. A Ruby class also comes closer to
a C++ namespace than a Ruby module because a Ruby class can contain
instances of objects, and as far as I know this isn’t possible in a Ruby
module.

Sincerely,
Martin

2

“Martin Elzen” martinelzen@hotmail.com schrieb im Newsbeitrag
news:Sea2-F4Ky3hrbn1KPvI00017abd@hotmail.com…

Recently someone pointed out that in his opinion there was just one
thing
Ruby was missing, which was something like C++ namespaces. Someone else
replied that in that case the OP should use Ruby modules. That’s not
exactly true, IMO. In C++ the most significant difference between
namespaces and classes is that namespaces are open, and classes are
shut.

There are others: you can’t instantiate a namespace.

Meaning that you can always add things to an already defined namespace,
but
you can not add anything to an existing class (unless you happen to have
the
source code of that class). In contrast, Ruby classes are always open,
you
can always add things to them, etc. , so in that way Ruby classes are
like
C++ namespaces. IMO if you want to achieve C+±like namespaces in Ruby,
you’d be best off by using a Ruby class. A Ruby class also comes closer
to
a C++ namespace than a Ruby module because a Ruby class can contain
instances of objects, and as far as I know this isn’t possible in a Ruby
module.

module Foo
SOMETHING = “something”
@bar = “bar”
def self.bar; @bar; end
end
=> nil
Foo::SOMETHING
=> “something”
Foo::bar
=> “bar”

I beg to differ: first, your statement isn’t true (if I understood you
correctly). Second, modules are not meant to be instantiated directly,
which is the same with C++ namespaces.

Kind regards

robert