From: "Gerardo Santana Gómez Garrido" <gerardo.santana@...>
Date: 2005-12-29T15:07:58+09:00
Subject: Re: Locking classes?

2005/12/28, Eero Saynatkari <ruby-ml@magical-cat.org>:
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> (Sorry if this is a duplicate.)
>
> On 2005.12.29 14:04, Gerardo Santana G�mez Garrido
> <gerardo.santana@gmail.com> wrote:
> > 2005/12/28, Max Eskin <kurtkilgor@yahoo.com>:
> > > Hi,
> > > I am just starting to use Ruby. I'm wondering, once a class has been
> > > declared, is there any way to lock it to prevent further methods from
> > > being defined? In other words is there a way to make Ruby act like a
> > > static language for some classes?
> >
> > Use Module#freeze
> >
> > class A
> >   def self.f(a)
> >     a + 1
> >   end
> > end
> >
> > puts A.f(1)   # => 2
> >
> > A.freeze
> >
> > #=> runtime error: "can't modify frozen object (TypeError)"
> > class A
> >   def self.f(a)
> >     a - 1
> >   end
> > end
> >
> > puts A.f(1)
>
> One can still A.dup, but I think this is a reasonable way :)

The original poster was concerned about adding methods. In such case
#dup is inoffensive.

--
Gerardo Santana