LazyMapper

lazymapper.py

# -*- coding: utf-8 -*-

class LazyMapperItem(object):
    def __init__(self, item, mapping):
        self.__item = item
        self.__mapping = mapping
    
    def __getattr__(self, name):
        try:
            real_name = self.__mapping[name]
        except KeyError:
            real_name = name
        return getattr(self.__item, real_name)
    
    def __getitem__(self, key):
        try:
            real_key = self.__mapping[key]
        except KeyError:
            real_key = key
        return self.__item[real_key]


class LazyMapper(object):
    def __init__(self, iterable, mapping=None, **kwargs):
        self.__iterable = iterable
        self.__iterator = iter(iterable)
        if mapping:
            self.__mapping = mapping
        else:
            self.__mapping = kwargs
        self.i = 0
    
    def __iter__(self):
        return self
    
    def next(self):
        return LazyMapperItem(self.__iterator.next(), self.__mapping)


class Person(object):
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
    def __getitem__(self, key):
        return getattr(self, key)

if __name__ == "__main__":
    persons = []
    persons.append(Person("Alice", 12))
    persons.append(Person("Bob", 13))
    
    mapping = {'nafn': 'name', 'aldur': 'age'}
    
    l = LazyMapper(persons, nafn='name', aldur='age')
    
    for p in l:
        print p['nafn'], p.aldur