/// <summary>
/// Initializes a new instance of the <see cref="MathExpressionFunctionNode"/> class.
/// </summary>
/// <param name="expressionType"></param>
/// <param name="functionNameFragment">The function name fragment.</param>
/// <param name="subNodes">The sub nodes (parameters).</param>
/// <param name="function">The delegate to calculate function value.</param>
/// <exception cref="ArgumentException">null sub node</exception>
public MathExpressionFunctionNode(
ExpressionTypeDescriptor expressionType,
ISourceCodeFragment functionNameFragment,
IEnumerable <IParsingProduct> subNodes,
Func <object[], object> function)
: base(expressionType, functionNameFragment, subNodes)
{
_function = function;
if (SubNodes.Cast <IExecutableExpressionNode>().Any(n => n == null))
{
throw new ArgumentException("null sub node");
}
}