/// <summary>
/// Writes the contents of this spreadsheet to dest using an XML format.
/// The XML elements should be structured as follows:
/// <spreadsheet IsValid="IsValid regex goes here"><cell name="cell name goes here" contents="cell contents go here"></cell><cell name="cell name goes here" contents="cell contents go here"></cell><cell name="cell name goes here" contents="cell contents go here"></cell></spreadsheet>
/// The value of the IsValid attribute should be IsValid.ToString()
/// There should be one cell element for each non-empty cell in the spreadsheet.
/// If the cell contains a string, the string (without surrounding double quotes) should be written as the contents.
/// If the cell contains a double d, d.ToString() should be written as the contents.
/// If the cell contains a Formula f, f.ToString() with "=" prepended should be written as the contents.
/// If there are any problems writing to dest, the method should throw an IOException.
/// </summary>
/// <param name="dest"></param>
/// <exception cref="System.NotImplementedException"></exception>
public override void Save(TextWriter dest)
{
using (var sw = new StringWriter())
{
using (var xw = XmlWriter.Create(sw))
{
xw.WriteStartDocument();
xw.WriteStartElement("spreadsheet");
xw.WriteAttributeString("IsValid", IsValid.ToString());
foreach (Cell c in cds.getCells())
{
xw.WriteStartElement("cell");
xw.WriteAttributeString("name", c.name);
//gotta <3 lambdas!
xw.WriteAttributeString("contents",
(c.contents is string?(string)c.contents:
(c.contents is double?c.contents.ToString() :
(c.contents is Formula ? "=" + c.contents.ToString() :
pretendToReturnStringButActuallyThrowAnException()))));
xw.WriteEndElement();
}
xw.WriteEndElement();
xw.WriteEndDocument();
}
dest.Write(sw.ToString());
}
Changed = false;
}
public static IEnumerable <string> SummonNames(CellDS cds)
{
//this overly complicated statement returns all nonempty cell names
return((cds.getCells()).Select(c => c.contents is string?((string)c.contents == "" ? "" : c.name) : c.name).Except(new HashSet <string>()
{
""
}));
}