Re: [PyGiNaC-users] Python lists of GiNaC objects?

[Richard B. K. <kr...@gi...>]

Hi!

On Wed, 14 Sep 2005, Jonathan Brandmeyer wrote:
[...]
> The ex will be automatically converted back to a numeric when wrapping
> it as an object, and list::append() automatically attempts to
> wrap/convert any argument it gets in/to a Python object, so just use
> 	result.append( -GiNaC::numeric(x_split.quotient));

Okay, thanks a lot.  It works just fine with your suggestions applied.

[...]
> If you saw manual refcount management in the PyGiNaC code it should be
> limited to the custom rvalue converter registration code.  In general,
> you can just rely on class object's automatic refcount management.

Yeah, I came across this stuff in PyGiNaC's file lst.cpp.
lst_to_python::convert(const GiNaC::lst&) is where I copied from.

> This is because 'l' is actually a Python list, it isn't a GiNaC::exlist
> (sp?) pretending to be a Python list.  The python list's __str__ method
> (invoked by the print statement) annoyingly invokes the __repr__ method
> of its containees rather than __str__.

Let me try to understand: Is this a feature?

>                                        __repr__ isn't defined by
> PyGiNaC's classes, so you get the default behavior: the address of the
> wrapping PyObject.

Why not define it?

>                     There are (at least) two workarounds.
[...]

Both workarounds appear cumbersome to me.

Best wishes
  -richy.
-- 
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>