html.fs

module Html = 

    type HtmlNode = 
        | HtmlElement of name:string * attribute:HtmlAttribute list
        | HtmlText of content:string *parent:HtmlNode

    and HtmlAttribute =  
        | HtmlAttribute of name:string * value:string * parent:HtmlNode

    let createElement name attrs =
        let toAttributes element = [ for name, value in attrs -> HtmlAttribute(name, value, element)]
        let rec element = HtmlElement(name, attributes)
        and attributes = toAttributes element
        element

Gives the error Recursive values cannot appear directly as a construction of the type 'HtmlNode' within a recursive binding. This feature has been removed from the F# language. Consider using a record instead.