Unregister functions & constants

[mibe]

Add the ability to remove functions & constants from the CalculationEngine.

[mibe]

I'm using "a" to "z" as variables. To achieve this I had to remove "e" as the Euler's number constant. And since I was already into it, I implemented a method for removing functions, too.

Since I'm currently using version 0.8.7, I implemented a reflection hack for this again:

/// <summary>
/// Remove a constant of the calculation engine.
/// </summary>
/// <param name="engine">Instance of the engine</param>
/// <param name="constantName">Name of the constant</param>
/// <returns>TRUE if the constant was removed successfully.</returns>
public static bool RemoveConstant(CalculationEngine engine, string constantName)
{
	// Retrieve ConstantRegistry
	ConstantRegistry registry = (ConstantRegistry)getProperty(engine, "ConstantRegistry");

	// Retrieve & invoke method for converting the constant name
	MethodInfo method = registry.GetType().GetMethod("ConvertConstantName", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.InvokeMethod);
	constantName = (String)method.Invoke(registry, new object[] { constantName });

	// Retrieve internal Dictionary
	Dictionary<string, ConstantInfo> constants = (Dictionary<string, ConstantInfo>)getField(registry, "constants");

	return constants.Remove(constantName);
}

private static object getProperty(object @object, string propertyName)
{
	PropertyInfo property = @object.GetType().GetProperty(propertyName, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetProperty);
	return property.GetValue(@object);
}

private static object getField(object @object, string fieldName)
{
	FieldInfo field = @object.GetType().GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField);
	return field.GetValue(@object);
}

[pieterderycke]

Jace 0.9 now has a parameter in the constructor of CalculcationEngine to prevent loading the default contstants

[mibe]

I saw that, thanks. Still, removing unwanted constants and functions is a nice feature, IMHO.

[pieterderycke]

The main issue, I see is that it might mess up the cache of generated formulas if some functions are suddenly gone. But I will give the request an additional thought.