Fluent interfaces and leaky abstractions

Question

What is a fluent interface? I can\'t find a good definition of this, but all I get are long code examples in a language I am not very familiar with (e.g. C++).

Also, wha

Answer 1

In a fluent interface, a object's methods will return a reference to the object, so that you can chain the method calls together.

For example, in NValidate, I did this to simplify parameter validation:

public City GetCity(string zipCode)
{
   zipCode.Assert("zipCode").IsNotNullOrEmpty().HasLength(5,10).Matches("\\d[5]-\\d[4]");
   // Continue processing
}

I can't speak to leaky abstractions, though.