[pygccxml-development] Order of enum values

[Matthias B. <ba...@ir...>]

Hi,

as I still have the problem that the order of enum values changes 
between two identical runs of pyplusplus (when the cache is used) I had 
a closer look at why this is the case. The problem is that the values of 
an enum are stored inside a dict and the order of those values may 
change when the dict is pickled and unpickled (usually this is ok as 
there is no order defined on the values of a dict).

Now I'm not sure what the best way to fix this is. The values in 
enumeration_t are stored as a dict: name(str) -> value(int). For 
example, the enum

   enum MColorType { kRGB, kHSV, kCMY, kCMYK };

is stored as the following dict (in an arbitrary order):

   {u'kCMY': u'2', u'kHSV': u'1', u'kRGB': u'0', u'kCMYK': u'3'}

Now I have several questions:

- A comment in the source code says that the value part is stored as an 
int but obviously it's a unicode string containing an int. Is this a 
bug? Could the value actually also be something else than an int?

- Are those integer values ever used? The generated code looks like this:

         bp::enum_<MColor::MColorType>("MColorType")
             .value("kCMY", MColor::kCMY)
             .value("kHSV", MColor::kHSV)
             .value("kRGB", MColor::kRGB)
             .value("kCMYK", MColor::kCMYK)
             .export_values()
             ;

Now what I'd like to have is a scheme that always produces the same 
order. There are several options how this could be implemented:

- Store the values inside a list instead of a dict. The items can be 
either just the enum names or tuples (name, value) if the value is still 
required somewhen.

- The code creator could sort the enum names according to their value 
and then use this order to write them out.


To me the first option seems to be the right one as an enum actually 
*is* an ordered construct. But I don't know the entire pyplusplus code, 
so maybe there are cases where a value has to be looked up quickly which 
justifies using a dict.
So, Roman, which approach would you prefer? (I might have a go at fixing 
it myself then)

- Matthias -