[reportlab-users] pycanvas.py

[Christoph Zwerschke]

Am 28.11.2013 12:15, schrieb Robin Becker:

> It is a module that implements a reporting proxy with a canvas that

> records all access calls and attribute settings etc etc. This fails

> under python3 because of differences between old and new style classes.


That difference is explained here:
http://docs.python.org/2/reference/datamodel.html

Essentially, what you need to do is add some more of the special methods 
to the PDFAction class, i.e. implement __str__ in the same way as it is 
done for __hash__ already.

I also wonder whether the PDFAction class can be simplified like this:

###

class PDFAction(object):
     """Base class to fake method calls or attributes on Canvas"""

     def __init__(self, parent, action) :
         self.__attr = getattr(parent._underlying, action)

     def __str__(self):
         return str(self.__attr)

     def __repr__(self):
         return repr(self.__attr)

     def __getattr__(self, name):
         """Probably a method call on an attribute, returns real one."""
         return getattr(self.__attr, name)

     def __call__(self, *args, **kwargs) :
         """The fake method is called, print it then call real one."""
         if not self._parent._parent._in :
             self._precomment()
             self._postcomment()
         self._parent._parent._in += 1
         retcode = self.__attr(*args, **kwargs)
         self._parent._parent._in -= 1
         return retcode

     def __hash__(self) :
         return hash(self.__attr)

     def _precomment(self) :
         print('%s(__dict__=%s)._precomment()' %
                 (self.__class__.__name__,repr(self.__dict__)))

     def _postcomment(self) :
         print('%s(__dict__=%s)._postcomment()' %
                 (self.__class__.__name__,repr(self.__dict__)))

###

-- Christoph