On 01/05/2013 05:49 AM, someone wrote: > On 01/05/2013 02:30 AM, Dave Angel wrote: > <snip> >> >> Function objects are enormously useful, as you get more adept at using >> Python. > > Ok, I'll look forward to that. Recently I had some problems with > pass-by-value vs pass-by-reference. I googled the problem and found > that by default python passes by reference.
Pascal has two calling conventions (value and reference). C always calls by value. C++ adds a call by reference, and maybe later C standards have added it as well. Python always calls by object. In fact, one could argue that there are no values (in the C sense) in Python. All names, and all attributes, and all slots in collections, are references to objects. So when you call a function, what you're doing is telling the function how to reference the same object(s). The usual way to say that is that the function call binds a new name to an existing object. If that object is mutable, then perhaps you wanted to do a copy first. Or perhaps you didn't. As you say, you debugged the program to find out. > I then debugged my program and finally found out that I should make a > copy (a new object) of the variable, before I passed it to my > function. And THIS solved my problem. But in C/C++ I think the default > is to pass by value, so this error in my program was a bit > unexpected... Anyway, I feel python is a great language for doing > things much faster than I could possibly do in C/C++. > > I also have on my todo-list to take my opengl-program and make it into > an executable. I mainly sit on a linux-pc but I want to distribute my > opengl program for windows (which has most users). I've found > something on google for py2app, cx_Freeze, bbfreeze and Freeze and I > hope this cross-platform thing does not cause too many problems... I > tried one of these tools a few weeks ago but I think I only succeeded > with a very simple hello-world program... Anyway, that's a problem > I'll investigate in a few months when I think/hope my opengl program > is finished... > -- DaveA -- http://mail.python.org/mailman/listinfo/python-list
