Re[2]: [Haskell-cafe] Interesting Thread on OO Usefulness (scala mailing list)
Hello Wolfgang, Tuesday, May 5, 2009, 8:27:17 PM, you wrote: i know two problems in Haskell/GHC that require OO-loke features - extensible exceptions and GUI widget types hierarchy Note that you don’t need different types for different kinds of GUI widgets if you use Functional Reactive Programming (FRP). You need different types if you use OO because you have to explicitely modify widgets after you have created them, and what modifications you are allowed to do, depends on the kind of widget. With FRP, you specify the behavior over all time when you create the widget, so no need for later method calls. (i don't know anything about FRP) i think it doesn't change anything. the main reason why i need common operations is because i write generic procedures. another erason os what i can't remember 100 individual 'setSize' operations for 100 types of widgets. so we need to have some generic names, short of they are used due initialization or later -- Best regards, Bulatmailto:bulat.zigans...@gmail.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re[2]: [Haskell-cafe] Interesting Thread on OO Usefulness (scala mailing list)
Hello Mads, Monday, May 4, 2009, 7:01:16 PM, you wrote: i know two problems in Haskell/GHC that require OO-loke features - extensible exceptions and GUI widget types hierarchy Yes, type hierarchies require OO. But, do we really need to represent different widget-types in a hierarchy? An alternative to a big hierarchy would be to let different widget-types implement different type classes. We could have type classes like MouseEvents, KeyboardEvents, Activated, ... there is obvious difference between OOP and type class hierarchies - OOP ones includes data fields. (somewhat close functionality provided by extensible records, but they are not in GHC nor provide strong type-checking) this means a lot of boilerplate code written, i.e. we lose compared to OOP -- Best regards, Bulatmailto:bulat.zigans...@gmail.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
