"Dave Thomas" <Dave / PragmaticProgrammer.com> wrote in message
news:S95b7.42087$WD1.2180821 / e420r-atl2.usenetserver.com...
> stesch / no-spoon.de (Stefan Scholl) writes:

> In Ruby, it is generally wrong to check the type of an argument by
> asking about it's class. In statically typed languages, a class

I agree about not making any explicit typechecking. But I believe there is
some middleground:

Some time back I asked a question about interfaces in Ruby. The conclusion
was, that you could check the module using is_a. You could even create empty
modules to define an interface.
For some purposes I think this is the right approach. You could for example
include a module BasicContainer in the triple class, which could be tested.
A test for is_a(Array) or is_a(BasicContainer) would then be appropriate if
you want to do some type checking.

Mikkel