typed lists

gistfile1.txt

from datetime import datetime, date
from decimal import Decimal

class TypedList(list):
    '''assumes subclassed with attribute _type constructor'''
    @classmethod
    def gen_type(cls, iterable):
        return (cls._type(i) for i in iterable)
    def __init__(self, iterable=()):
        super(TypedList, self).__init__(self.gen_type(iterable))
    def insert(self, index, object):
        super(TypedList, self).insert(index, self._type(object))
    def extend(self, iterable):
        super(TypedList, self).extend(self.gen_type(iterable))
    def __iadd__(self, other):
        return super(TypedList, self).__iadd__(self.gen_type(other))
    def append(self, object):
        super(TypedList, self).append(self._type(object))
    def __setslice__(self, i, j, sequence):
        super(TypedList, self).__setitem__(self, i, j, self.gen_type(sequence))
    def __setitem__(self, key, value):
        super(TypedList, self).__setitem__(key, self._type(value))
        

# 'string[]'
class StrList(TypedList):
    _type = str


# 'float[]'
class FloatList(TypedList):
    _type = float


# 'int[]'
class IntList(TypedList):
    _type = int


# 'decimal[]' # ???
class DecimalList(TypedList):
    '''must convert floats to strings before giving to list'''
    _type = Decimal


# 'date[]'
class DateList(TypedList):
    '''can convert from date 3-tuple'''
    @staticmethod
    def _type(obj):
        if isinstance(obj, date):
            return obj
        if isinstance(obj, datetime):
            return obj.date
        return date(*obj)


# 'time[]'
class TimeList(TypedList):
    '''can convert from timetuple, i.e. 3+tuple'''
    @staticmethod
    def _type(obj):
        if isinstance(obj, datetime):
            return obj
        if isinstance(obj, date):
            return datetime(*obj.timetuple()[:6])
        if isinstance(obj, (int, long)):
            return datetime.fromtimestamp(obj)
        return datetime(*obj)
        

sl = StrList('0123')
print(sl)
il = IntList(sl)
print(il)
fl = FloatList(il)
print(fl)
dl = DecimalList(sl)
dl += il
print(dl)
datel = DateList()
datel.append(date.today())
datel.extend(((1,1,1),(2,2,2)))
print(datel)
timel = TimeList(datel)
timel.append(datetime.now())
print(timel)