Re: The difference between PythonExtension and ExtensionObject

[Barry S. <ba...@ba...>]

On 1 Apr 2010, at 07:52, B A wrote:

> Hi, guys,
> PyCXX is great. :) 
> After reading the code, I am not clear about the relationship between PythonExtension and ExtensionObject.
> Some usage in the sample code was 
> 
> Py::ExtensionObject<range> rheap( new range(1, 10, 2) );
> 
> and 
> 
> range is based on PythonExtension.
> 
> 
> How to use ExtensionObject?

ExtensionObject<type> is an object that will only accept a Py::Object that is of <type>.
Use this to make sure you have been passed one of your objects.

If I wanted to make sure a Py::Object was a String I could write:

	Py::String s( args[2] );

If args[2] is not a string then an exception is thrown.

Now if I want to make sure I get a MyType then I'd code:

	ExtensionObject<MyType> s( args[2] );

If args[2] is not a MyType then an exception is thrown.

Barry