Incomplete, but a promising start. I like either types.

HTMLWriter.swift

// HTMLWriter.swift
// Douglas Hill, June 2014

// HTML syntax documentation: http://www.w3.org/TR/html-markup/syntax.html

enum HTMLContent {
	case Element(HTMLElement)
	case Text(String)
}

struct HTMLElement {
	var name: String
	var attributes: Dictionary<String, String>
	var contents: HTMLContent[]
}

extension HTMLElement: Printable {
	var description: String {
		
		var attributesString = attributes.count >= 1 ? " " : ""
		for (key, value) in attributes {
			attributesString += "\(key)=\"\(value)\""
		}
		
		var contentsString = ""
		for item in contents {
			switch item {
			case .Element(let element): contentsString += element.description
			case .Text(let text): contentsString += text
			}
		}
		return "<\(name)\(attributesString)>\(contentsString)</\(name)>"
	}
}

let title = HTMLElement(name: "h1", attributes: ["id": "main-title"], contents: [.Text("The "), .Element(HTMLElement(name: "em", attributes: [:], contents: [.Text("Title")]))])

println("\(title)")