Prettier - properly pprint of nested objects

If you are trying to output nested data structures, each of which is individually displayed as a dictionary representation, the nesting levels are not separated, such an output is difficult to perceive.

class PPrintMixin:
    def __str__(self):
        return str(self.__dict__)


SAMPLE_DICT = {'a': None}
SAMPLE_DICT['a'] = SAMPLE_DICT


class A(PPrintMixin):
    def __init__(self):
        self.attrs = ('a', 'b', 'c')
        self.a = 10
        self.b = B()
        self.c = {'a': 1, 'b': 2, 'c': 3}
        setattr(self, 'd\nd', {'a': 1, 'b': 2, 'c': 3})
        self.e = 'a\na'
        self.f = 'a' * 100
        self.g = self
        self.h = SAMPLE_DICT


class B(PPrintMixin):
    def __init__(self):
        setattr(self, 'a \n a', {'a': 1, 'b': {'a': 1, 'b': 2, 'c': 3}, 'c\nc': C()})
        self.b = [C(), 1]
        self.c = C()


class C(PPrintMixin):
    def __init__(self):
        self.a = ('b', 'c')
        self.b = 'a \n a'
        self.c = {}

You can expect the following output:

{'attrs': ('a', 'b', 'c'), 'a': 10, 'b': <__main__.B object at 0x1034b74c0>, 'c': {'a': 1, 'b': 2, 'c': 3}, 'd\nd': {'a': 1, 'b': 2, 'c': 3}, 'e': 'a\na', 'f': 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', 'g': <__main__.A object at 0x1033fb3a0>, 'h': {'a': {...}}}

But if you use a PPrintMixin instead of the standard one, then you can expect the following output:

{'a': 10,
 'd
   d': {'a': 1,
        'b': 2,
        'c': 3},
 'e': 'a
       a',
 'c': {'a': 1,
       'b': 2,
       'c': 3},
 'h': {'a': <RecursionError on 4304997312>},
 'b': {'a 
           a': {'a': 1,
                'b': {'a': 1,
                      'b': 2,
                      'c': 3},
                'c
                  c': {'a': ('b', 'c'),
                       'c': {},
                       'b': 'a 
                              a'}},
       'c': {'a': ('b', 'c'),
             'c': {},
             'b': 'a 
                    a'},
       'b': [<__main__.C object at 0x100bf3a60>, 1]},
 'attrs': ('a', 'b', 'c'),
 'f': 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
       aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa',
 'g': <RecursionError on 4307498032>}

If you want to create an own Mixin, just import MixinFactory. For example, you can use the endpoint argument. This is the name of the attribute that stores the list of arguments to print. Let's combine some Mixins, like this:

from prettier import MixinFactory

AttrsPrintMixin = MixinFactory(endpoint='attrs')
APrintMixin = MixinFactory(endpoint='a')


class A(AttrsPrintMixin):
    ...


class B(PrintMixin):
    ...


class C(APrintMixin):
    ...

The output will be:

{'a': 10,
 'b': {'c': {'b': 'a 
                    a',
             'c': {}},
       'b': [<__main__.C object at 0x100b478b0>, 1],
       'a 
           a': {'a': 1,
                'b': {'a': 1,
                      'b': 2,
                      'c': 3},
                'c
                  c': {'b': 'a 
                              a',
                       'c': {}}}},
 'c': {'a': 1,
       'b': 2,
       'c': 3}}