added a simple builder API to the std.dom API

stdlib/ktSrc/dom/Dom.kt

@@ -1,9 +1,8 @@
 package std.dom
 
+import std.*
 import org.w3c.dom.*
-import javax.xml.parsers.DocumentBuilder
-import javax.xml.parsers.DocumentBuilderFactory
-import std.getOrElse
+
 
 // Properties
 
@@ -19,6 +18,7 @@ set(value) {
     this.setAttribute("style", value)
 }
 
+// TODO can we come up with a better name; 'class' is a reserved word?
 var Element.cssClass : String
 get() = this.getAttribute("class").getOrElse("")
 set(value) {
@@ -32,4 +32,64 @@ inline fun Node.plus(child: Node?): Node {
         this.appendChild(child)
     }
     return this
-}
+}
+
+
+// Builder
+
+/*
+Creates a new element which can be configured via a function
+*/
+fun Document.createElement(name: String, init: Element.()-> Unit): Element {
+    val elem = this.createElement(name).sure()
+    elem.init()
+    return elem
+}
+
+/*
+Creates a new element to an element which has an owner Document which can be configured via a function
+*/
+fun Element.createElement(name: String, doc: Document? = null, init: Element.()-> Unit): Element {
+    val elem = ownerDocument(doc).createElement(name).sure()
+    elem.init()
+    return elem
+}
+
+/*
+Returns the owner document of the element or uses the provided document
+*/
+fun Element.ownerDocument(doc: Document? = null): Document {
+    val answer = if (doc == null) this.getOwnerDocument() else doc
+    if (answer == null) {
+        throw IllegalArgumentException("Element does not have an ownerDocument and none was provided for: ${this}")
+    } else {
+        return answer
+    }
+}
+
+/*
+Adds a newly created element which can be configured via a function
+*/
+fun Document.addElement(name: String, init: Element.()-> Unit): Element {
+    val child = createElement(name, init)
+    this.appendChild(child)
+    return child
+}
+
+/*
+Adds a newly created element to an element which has an owner Document which can be configured via a function
+*/
+fun Element.addElement(name: String, doc: Document? = null, init: Element.()-> Unit): Element {
+    val child = createElement(name, doc, init)
+    this.appendChild(child)
+    return child
+}
+
+/*
+Adds a newly created text node to an element which either already has an owner Document or one must be provided as a parameter
+*/
+fun Element.addText(text: String, doc: Document? = null): Element {
+    val child = ownerDocument(doc).createTextNode(text)
+    this.appendChild(child)
+    return this
+}