/// <summary>
/// Adds an individual formula function
/// </summary>
/// <param name="functionCall">A delegate pointing to the method you wish to add</param>
/// <remarks>
/// This function lets you add an individual formula function by specifying a delegate pointing to it. The method that
/// the delegate refers to must be tagged with the appropriate
/// <see cref="T:ciloci.FormulaEngine.FormulaFunctionAttribute">attribute</see>.
/// </remarks>
/// <exception cref="T:System.ArgumentException">
/// The method that the delegate points to is not tagged with the required
/// attribute
/// </exception>
/// <exception cref="T:System.InvalidOperationException">
/// The function was called while formulas are defined in the formula engine
/// <para>A function with the same name is already defined</para>
/// </exception>
public void AddFunction(FormulaFunctionCall functionCall)
{
FormulaEngine.ValidateNonNull(functionCall, "functionCall");
ValidateEngineStateForChangingFunctions();
var attr =
(FormulaFunctionAttribute)
Attribute.GetCustomAttribute(functionCall.Method, typeof(FormulaFunctionAttribute));
if (attr == null)
{
throw new ArgumentException("The function does not have a FormulaFunctionAttribute defined on it");
}
var info = new FunctionInfo(functionCall, attr);
AddFunctionInternal(info);
}
public FunctionInfo(FormulaFunctionCall target, FormulaFunctionAttribute attr)
{
FunctionTarget = target;
FunctionAttribute = attr;
string targetName = target.Method.Name;
if (attr.Names != null && attr.Names.Length > 0)
{
int addlNamesLen = attr.Names.Length;
Names = new string[addlNamesLen + 1];
Array.Copy(attr.Names, 0, Names, 1, addlNamesLen);
}
else
{
Names = new string[1];
}
Names[0] = targetName;
Volatile = attr.IsVolatile;
}
/// <summary>
/// Go through all methods of a type and try to add them as formula functions
/// </summary>
private void AddFormulaMethods(Type targetType, IDelegateCreator creator)
{
ValidateEngineStateForChangingFunctions();
BindingFlags flags = BindingFlags.NonPublic | BindingFlags.Public | creator.Flags;
foreach (MethodInfo mi in targetType.GetMethods(flags))
{
var attr = (FormulaFunctionAttribute)Attribute.GetCustomAttribute(mi, typeof(FormulaFunctionAttribute));
if (attr != null)
{
FormulaFunctionCall d = creator.CreateDelegate(mi.Name);
if (d == null)
{
throw new ArgumentException(String.Format("The method {0} is marked as a formula function but does not have the correct signature", mi.Name));
}
var info = new FunctionInfo(d, attr);
AddFunctionInternal(info);
}
}
}
