/// <summary>
/// Python method may have the following function attributes set to control how they're exposed:
/// - _clr_return_type_ - method return type (required)
/// - _clr_arg_types_ - list of method argument types (required)
/// - _clr_method_name_ - method name, if different from the python method name (optional)
/// </summary>
/// <param name="methodName">Method name to add to the type</param>
/// <param name="func">Python callable object</param>
/// <param name="typeBuilder">TypeBuilder for the new type the method/property is to be added to</param>
private static void AddPythonMethod(string methodName, PyObject func, TypeBuilder typeBuilder)
{
if (func.HasAttr("_clr_method_name_"))
{
using (PyObject pyMethodName = func.GetAttr("_clr_method_name_"))
{
methodName = pyMethodName.ToString();
}
}
using (PyObject pyReturnType = func.GetAttr("_clr_return_type_"))
using (PyObject pyArgTypes = func.GetAttr("_clr_arg_types_"))
{
var returnType = pyReturnType.AsManagedObject(typeof(Type)) as Type;
if (returnType == null)
{
returnType = typeof(void);
}
if (!pyArgTypes.IsIterable())
{
throw new ArgumentException("_clr_arg_types_ must be a list or tuple of CLR types");
}
var argTypes = new List <Type>();
foreach (PyObject pyArgType in pyArgTypes)
{
var argType = pyArgType.AsManagedObject(typeof(Type)) as Type;
if (argType == null)
{
throw new ArgumentException("_clr_arg_types_ must be a list or tuple of CLR types");
}
argTypes.Add(argType);
}
// add the method to call back into python
MethodAttributes methodAttribs = MethodAttributes.Public |
MethodAttributes.Virtual |
MethodAttributes.ReuseSlot |
MethodAttributes.HideBySig;
MethodBuilder methodBuilder = typeBuilder.DefineMethod(methodName,
methodAttribs,
returnType,
argTypes.ToArray());
ILGenerator il = methodBuilder.GetILGenerator();
il.DeclareLocal(typeof(object[]));
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Ldstr, methodName);
il.Emit(OpCodes.Ldnull); // don't fall back to the base type's method
il.Emit(OpCodes.Ldc_I4, argTypes.Count);
il.Emit(OpCodes.Newarr, typeof(object));
il.Emit(OpCodes.Stloc_0);
for (var i = 0; i < argTypes.Count; ++i)
{
il.Emit(OpCodes.Ldloc_0);
il.Emit(OpCodes.Ldc_I4, i);
il.Emit(OpCodes.Ldarg, i + 1);
if (argTypes[i].IsValueType)
{
il.Emit(OpCodes.Box, argTypes[i]);
}
il.Emit(OpCodes.Stelem, typeof(object));
}
il.Emit(OpCodes.Ldloc_0);
if (returnType == typeof(void))
{
il.Emit(OpCodes.Call, typeof(PythonDerivedType).GetMethod("InvokeMethodVoid"));
}
else
{
il.Emit(OpCodes.Call,
typeof(PythonDerivedType).GetMethod("InvokeMethod").MakeGenericMethod(returnType));
}
il.Emit(OpCodes.Ret);
}
}