From: Jeff Cohen <cohen.jeff@...>
Date: 2005-12-07T11:52:25+09:00
Subject: Interfaces in Ruby?

I'm new to Ruby - actually new to dynamically typed languages in 
general.  I'm from more of a C++ and C# (strongly-typed and 
statically-typed) background.

One thing I'm trying to wrap my brain around is the lack of explicit 
interface definitions. In C# we use interfaces so that client code can 
program against an abstract interface, and then you can give that client 
any concrete implementation of that interface as needed.  Interfaces 
provide a level of abstraction/indirection that increase reusability and 
testability.

Now, in Ruby, I like the "walk like a duck" approach.  Actually, it's 
similar to C++ templates which are very powerful.

But there are two things that I worry about as I forge ahead in my new 
Ruby lifestyle:

1. In C# I can write code that can query an object for the interfaces it 
implements to find out what I can do with it.  (Rarely used but 
sometimes a lifesaver).  In Ruby I guess I have to use .methods to find 
out what methods it implements?

2. In C# I can insure that a function is given an object that implements 
a certain interface.  If I don't, it's a compile-time error and I know 
it before I ship it.  In Ruby, I won't know if I accidentally pass in 
the wrong object until runtime.  I might not catch it before I ship the 
code.

Can anyone provide some enlightenment?

Thanks!
Jeff

-- 
Posted via http://www.ruby-forum.com/.