Re: [Haskell-cafe] Constraints at construction

On Thu, 9 Oct 2008, Iain Barnett wrote:

If I were to create an object in C#, for instance, I could add code to the constructor that might limit the type further e.g.

public class Car { string model; int wheels;

public Car ( string model, int no_of_wheels ) { if ( no_of_wheels <= 2 ) { throw new Exception( "a car must have at least 3 wheels"); } this.model = model; this.no_of_wheels = no_of_wheels; } }

I think it is not the right way to handle the number of wheels with an exception. This should be considered an error. http://www.haskell.org/haskellwiki/Error