Hi all, I'm now using existential types. I avoided learning about them because the name sounded so highly technical and obscure it did not occur to me they could be related to OO. Thanks, -John On 12/7/06, John Ky wrote:

Hi,

I've got an object model that I have a difficult time conceptualising how it might look like in Haskell:

class Element { }

class Inline : Element { }

class ParentInline : Inline { List<Inline> children; }

class Bold : ParentInline { } class Underline : ParentInline { }

class Link : ParentInline { String link; }

class Text : Inline { String text; }

class Block : Element { }

class Paragraph : Block { List<Inline> paragraph; }

class Heading : Block { List<Inline> heading; }

class Document : Element { List<Block> blocks; }

How best to represent this OO data model in Haskell?

Thanks

-John