[C++-sig] Re: Returning reference to member variable that's a basic type

[Joel Gerard]

Hmmm... I see what you mean.  Couldn't you map an int reference to something like:

class IntegerReference :
    def __setattr__(self, name, value) :
        #BPL code here 
       
    def __getattr__ (self, name) :
        #BPL code here

Then you could do something like:
i = Obj.FnThatReturnsAnIntRef()
i.value = 45

IntegerReference would keep a pointer to the original integer (I'm assuming you can do this: keep
the address of the original variable as a python int or something, and then deference it in C?). 
Then set and get would deference the pointer, and get/set the value respectively.

It's a pity that one can't overload the assignment operator in python (not that I've seen anyhow).
 The "i.value" mechanism is not the cleanest, and I'd prefer to do "i=5" but I'd rather have some
mechanism than nothing.  Perhaps there is a better way. I fairly new to python.

Thanks for the quick response. ;)

Joel


--- David Abrahams <dave at boost-consulting.com> wrote:
> Joel Gerard <llywelyn.geo at yahoo.com> writes:
> 
> > I hope this doesn't get me the dumb question of the day award but...
> >
> > How do you return a pointer/reference to a member variable(a basic type) and modify it from
> > python?
> 
> You don't.  Basic types get mapped to Python ints, longs, and
> strings, all of which are immutable.  YOu can't modify them.
> 
> Decide what interface you'd like to see for this code in Python, code
> up a pure-Python mock-up which does what you want, and we can discuss
> how to achieve it with BPL.
> 
> -- 
> Dave Abrahams
> Boost Consulting
> www.boost-consulting.com
> 
> 
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> C++-sig at python.org
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