My first attempt at subclassing....Gahh!

Robin Siebler robin.siebler at palmsource.com
Tue Sep 14 05:10:13 CEST 2004


I want to use filecmp.dircmp, but it only prints to the screen, there
is no way to capture the output.  So I thought that I should simply be
able to subclass it to return a list (Danger!  Danger, Will! Simple
and Subclass should never be used in the same sentence!).  However, my
first attempt (pathetic as it may be), results in an error that I
don't understand.  Obviously, I'm doing something wrong, but what? 
I'm using Python 2.2.3 and the error I get is 'TypeError: cannot
create 'instance method' instances'.

import filecmp

class dircmp(filecmp.dircmp):
    def my_report_partial_closure(self):
        output= []
        self.report()
        for x in self.subdirs.keys():
            output.append(self.subdirs[x].report())
        return output

class report(filecmp.dircmp.report):
        def my_report(self): # Print a report on the differences
between a and b
        # Output format is purposely lousy
            output = []
            output.append('diff', self.left, self.right)
            if self.left_only:
                self.left_only.sort()
                output.append('Only in', self.left, ':',
self.left_only)
            if self.right_only:
                self.right_only.sort()
                output.append('Only in', self.right, ':',
self.right_only)
            if self.same_files:
                self.same_files.sort()
                output.append('Identical files :', self.same_files)
            if self.diff_files:
                self.diff_files.sort()
                output.append('Differing files :', self.diff_files)
            if self.funny_files:
                self.funny_files.sort()
                output.append('Trouble with common files :',
self.funny_files)
            if self.common_dirs:
                self.common_dirs.sort()
                output.append('Common subdirectories :',
self.common_dirs)
            if self.common_funny:
                self.common_funny.sort()
                output.append('Common funny cases :',
self.common_funny)



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