From: ThoML <micathom@...>
Date: 2008-02-25T05:59:55+09:00
Subject: Re: Ruby type-safe? Ruby strongly/weakly typed? Ruby pitfalls?

> While a type-identifier (or class-identifier) in Ruby should rather be
> looked upon as a Variable.

Actually a class rather can be thought of as an object assigned to a
constant (if I'm not mistaken):

irb(main):002:0> class A
irb(main):003:1> end
=> nil
irb(main):004:0> A.class
=> Class
irb(main):006:0> A.superclass
=> Object

> if you have a function F that takes an argument of type A and returns
> a result of type A,
> well, actually the type A may have changed between the point of
> invocation of the function and the point where the result is returned.

You mustn't forget that a ruby program isn't a closed system where
every
part is defined at compile time. If you remove eval & friends, you
could
perform some whole system analysis and to some extent formally prove
the
correctness of a program, I think. This isn't really news though.