/// <summary>
/// 获取源代码的规范格式
/// <para>语法分析的副产品</para>
/// </summary>
/// <param name="tree">语法树</param>
/// <returns></returns>
public static double GetValue(this SyntaxTree <EnumTokenTypeExpression, EnumVTypeExpression, TreeNodeValueExpression> tree)
{
if (tree == null)
{
return(double.NaN);
}
var tmpTree = tree.Clone() as SyntaxTree <EnumTokenTypeExpression, EnumVTypeExpression, TreeNodeValueExpression>;
_GetValue(tmpTree);
return(double.Parse(tmpTree.Tag.ToString()));
}