#!/usr/bin/env python2.7

import pandas as pd

class SinkInto(object):
    def __init__(self, function, *args, **kwargs):
        self.args = args
        self.kwargs = kwargs
        self.function = function

    def __rrshift__(self, other):
        return self.function(other, *self.args, **self.kwargs)

    def __repr__(self):
        return "<SinkInto {} args={} kwargs={}>".format(
            self.function,
            self.args,
            self.kwargs
        )


def pipe(original):
    class PipeInto(object):
        function = original

        def __init__(self, *args, **kwargs):
            self.args = args
            self.kwargs = kwargs

        def __rrshift__(self, other):
            return self.function(other, *self.args, **self.kwargs)

        def __repr__(self):
            return "<SinkInto {} args={} kwargs={}>".format(
                self.function,
                self.args,
                self.kwargs
            )
    return PipeInto


@pipe
def select(df, *args):
    cols = [x for x in args]
    return df[cols]


@pipe
def rename(df, **kwargs):
    for name, value in kwargs.items():
        df = df.rename(columns={'%s' % name: '%s' % value})
    return df


df = pd.DataFrame({'one' : [1., 2., 3., 4., 4.],
                   'two' : [4., 3., 2., 1., 3.]})

df >> select('one') >> rename(one='first')

# Output
Traceback (most recent call last):
  File "decorator_test.py", line 58, in <module>
    df >> select('one') >> rename(one='first')
  File "decorator_test.py", line 31, in __rrshift__
    return self.function(other, *self.args, **self.kwargs)
  File "decorator_test.py", line 45, in select
    return df[cols]
TypeError: 'PipeInto' object has no attribute '__getitem__'