Re: [Haskell-cafe] Something that kind of resembles OO

Michael Mossey writes:

I notice in algebraic data defined with named fields, you can use the same name inside different constructors and then apply it to any data of that type.

data Vehicle = Car { ident :: String, wheel :: Circle } | Plane { ident :: String, stick :: Line }

f :: [Vehicle] -> [String] f = map ident

This is a little like fields in a base class.

I also see that a wrong use of accessor functions will compile but give a runtime error:

test = wheel (Plane "foo" (Line 1))

Well, it type-checks... -- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com