Swift Builder

gistfile1.swift

import Foundation

struct Builder {
  typealias Attributes = Dictionary<String, AnyObject>
  typealias Block = () -> ()
  typealias Visitor = (Node) -> ()
  
  class Node {
    var name : String
    var parent: Node? { didSet { level = parent!.level + 1} }
    var children = Node[]()
    var attr = Attributes()
    var block: Block?
    var level = 0
    var value : AnyObject?
    
    init( name: String) {
      self.name = name
    }
    
    func visit(before: Visitor?, after: Visitor?) {
      if let v = before { v(self) }
      for c in children { c.visit( before, after ) }
      if let v = after { v(self) }
    }
  }
  
  static let root = Node(name: "root")
  static var current = root
  
  static func node(name: String, attr : Attributes?, value: AnyObject?, block: Block ) {
    var n = Node(name: name)
    n.parent = current
    if let a = attr { n.attr = a }
    n.block = block
    n.value = value
    current.children += n
    current = n
    block()
    if let p = current.parent { current = p }
  }
  
  static func visit(before: Visitor?, after: Visitor?) {
    for c in root.children { c.visit(before, after) }
  }
}


func html(block: ()->()) { html(nil, block) }
func html(attr: Builder.Attributes?, block: ()->()) { Builder.node("html", attr: attr, value: nil,  block) }

func body(block: ()->()) { body(nil, block) }
func body(attr: Builder.Attributes? , block: ()->()) { Builder.node("body", attr: attr, value: nil, block) }

func head(block: ()->()) { head(nil, block) }
func head(attr: Builder.Attributes?, block: ()->()) { Builder.node("head", attr: attr, value: nil, block) }

func title(block: ()->()) { title(nil, nil, block) }
func title(attr: Builder.Attributes?, block: ()->()) { title(attr, nil, block) }
func title(value: AnyObject?, block: ()->()) { title(nil, value, block) }
func title(attr: Builder.Attributes?, value: AnyObject?, block: ()->()) { Builder.node("title", attr: attr, value: value, block) }

func div(block: ()->()) { div(nil, nil, block) }
func div(attr: Builder.Attributes?, block: ()->()) { div(attr, nil, block) }
func div(value: AnyObject?, block: ()->()) { div(nil, value, block) }
func div(attr: Builder.Attributes?, value: AnyObject?, block: ()->()) { Builder.node("div", attr: attr, value: value, block) }

func p(block: ()->()) { p(nil, nil, block) }
func p(attr: Builder.Attributes?, block: ()->()) { p(attr, nil, block) }
func p(value: AnyObject?, block: ()->()) { p(nil, value, block) }
func p(attr: Builder.Attributes?, value: AnyObject?, block: ()->()) { Builder.node("p", attr: attr, value: value, block) }

func a(block: ()->()) { a(nil, nil, block) }
func a(attr: Builder.Attributes?, block: ()->()) { a(attr, nil, block) }
func a(value: AnyObject?, block: ()->()) { a(nil, value, block) }
func a(attr: Builder.Attributes?, value: AnyObject?, block: ()->()) { Builder.node("a", attr: attr, value: value, block) }


func visit(before: Builder.Visitor?, after: Builder.Visitor?  = nil) {
  Builder.visit(before, after)
}


html {
  head {
    title( "Page Title" ) {}
  }

  body(["class":"bodyClass"]) {
    for i in 0..3 {
      div(["id":"div_\(i)"]) {
        p("Click ") {
          a(["href":"http://www.example.com/link\(i).html"], "link \(i+1)") {}
        }
      }
    }
  }
}



func repeat( item: String, n: Int) -> String {
  var s = ""
  for var i:Int=0; i<n; i++ { s += item }
  return s
}


visit( {
  let node = $0
  let r = repeat(" ", node.level*2)
  var tag = "\(r)<\(node.name)"
  for a in node.attr { tag += " \"\(a.0)\"=\"\(a.1)\"" }
  tag += ">"
  if let v:AnyObject = node.value { tag += "\(v)" }
  println(tag)
  },
  {
    let node = $0
    let r = repeat(" ", node.level*2)
    var tag = "\(r)</\(node.name)>"
    println(tag)
  } )


println([1,2,3,4,5].count)