Untitled1.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "import typing"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [],
   "source": [
    "T = typing.TypeVar(\"T\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [],
   "source": [
    "L = typing.List[typing.List[T]]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def f() -> L[int]:\n",
    "    return [[1, 2, 3]]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "class Column:\n",
    "    def mean(self) -> int:\n",
    "        return 0\n",
    "\n",
    "\n",
    "class GeoColumn(Column):\n",
    "    def length(self) -> int:\n",
    "        return 0"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "class Dataframe:\n",
    "    def __init__(self, cols):\n",
    "        self.cols = cols\n",
    "\n",
    "    def __getattr__(self, name):\n",
    "        return self.cols[name]\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "d = Dataframe({\"name\": Column(), \"location\": GeoColumn()})"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "0"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d.location.length()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "T = TypeVar(\"T\", bound=Dict[str, Column])\n",
    "\n",
    "K = TypeVar(\"K\", bound=KeyOf[T])\n",
    "\n",
    "\n",
    "class Dataframe(Generic[T]):\n",
    "    def __init__(self, cols: T):\n",
    "        self.cols = cols\n",
    "\n",
    "    def __getattr__(self, name: K) -> GetItem[T, K]:\n",
    "        return self.cols[name]"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.7.3"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 4
}