Create in F# XDocument with XDeclaration and namespace

In this example I will create the following XML in F#:

<?xml version="1.0" encoding="utf-8"?>

<w:document xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main">

  <w:body>

    <w:p>

      <w:r>

        <w:t>This is a test</w:t>

      </w:r>

    </w:p>

  </w:body>

</w:document>

Transferring C#-code is not straightforward because the constructor of XDocument does not accept the following code: new  XDocument(new XDeclaration("1.0", "utf-8", "true"), new XElement("document"))

//First create some helpers:

let xnameNs str ns = XName.Get(str, ns)

let xname str =

    xnameNs str "http://schemas.openxmlformats.org/wordprocessingml/2006/main"

let ns = XNamespace.Get("http://schemas.openxmlformats.org/wordprocessingml/2006/main")

let dec = new XDeclaration("1.0", "utf-8", "true")

let el =

    new XElement(xname "document",

        new XAttribute(XNamespace.Xmlns + "w", ns),

            new XElement(xname "body",

                new XElement(xname "p",

                    new XElement(xname "r",

                        new XElement(xname "t", "This is a test")

                        ))))

//Add them together:

let document = 

    let doc =new XDocument(dec)

    doc.AddFirst(el)

    doc

//And test:

document.Save(@"D:\Tmp\test1.xml")