{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# PSET 1: Bottom-Up Synthesis\n",
    "\n",
    "I follow Algorithm 1 in the BUSTLE paper:\n",
    "\n",
    "> Odena, A. *et al.* BUSTLE: Bottom-Up Program Synthesis Through Learning-Guided Exploration. in *9th International Conference on Learning Representations*; 2021 May 3-7; Austria.\n",
    "\n",
    "First, I import the required libraries."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "import itertools\n",
    "\n",
    "# argument parser for command line arguments\n",
    "import argparse\n",
    "\n",
    "# import arithmetic module\n",
    "# from arithmetic import *\n",
    "# from abstract_syntax_tree import OperatorNode\n",
    "from examples import example_set, check_examples\n",
    "import config"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "24"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "add_node = OperatorNode(Add(), [IntegerConstant(7), IntegerConstant(5)])\n",
    "subtract_node = OperatorNode(Subtract(), [IntegerConstant(3), IntegerConstant(1)])\n",
    "multiply_node = OperatorNode(Multiply(), [add_node, subtract_node])\n",
    "multiply_node.evaluate()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "First, I define variables as proxies for command-line arguments provided to the synthesizer."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "domain = \"arithmetic\"\n",
    "examples_key = \"addition\"\n",
    "examples = example_set[examples_key]\n",
    "max_weight = 3"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "First, I define a function to check that, across all input-output pairs, all inputs are of the same length and that argument types are consistent across inputs."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "I provide examples of arithmetic operations."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "class IntegerVariable:\n",
    "    '''\n",
    "    Class to represent an integer variable. Note that position is the position of the variable in the input.\n",
    "    For example, if the input is [4, 5, 6] and the variable is the third element (i.e., 6), then position = 2.\n",
    "    '''\n",
    "    def __init__(self, position):\n",
    "        self.value = None           # value of the variable, initially None\n",
    "        self.position = position    # position of the variable in the arguments to program\n",
    "        self.type = int             # type of the variable\n",
    "\n",
    "    def assign(self, value):\n",
    "        self.value = value\n",
    "\n",
    "class IntegerConstant:\n",
    "    '''\n",
    "    Class to represent an integer constant.\n",
    "    '''\n",
    "    def __init__(self, value):\n",
    "        self.value = value  # value of the constant\n",
    "        self.type = int     # type of the constant\n",
    "\n",
    "class Add:\n",
    "    '''\n",
    "    Operator to add two numerical values.\n",
    "    '''\n",
    "    def __init__(self):\n",
    "        self.arity = 2                  # number of arguments\n",
    "        self.arg_types = [int, int]     # argument types\n",
    "        self.return_type = int          # return type\n",
    "        self.weight = 1                 # weight\n",
    "\n",
    "    def __call__(self, x, y):\n",
    "        return x + y\n",
    "    \n",
    "    def str(x, y):\n",
    "        return f\"{x} + {y}\"\n",
    "\n",
    "class Subtract:\n",
    "    '''\n",
    "    Operator to subtract two numerical values.\n",
    "    '''\n",
    "    def __init__(self):\n",
    "        self.arity = 2                  # number of arguments\n",
    "        self.arg_types = [int, int]     # argument types\n",
    "        self.return_type = int          # return type\n",
    "        self.weight = 1                 # weight\n",
    "\n",
    "    def __call__(self, x, y):\n",
    "        return x - y\n",
    "    \n",
    "    def str(x, y):\n",
    "        return f\"{x} - {y}\"\n",
    "    \n",
    "class Multiply:\n",
    "    '''\n",
    "    Operator to multiply two numerical values.\n",
    "    '''\n",
    "    def __init__(self):\n",
    "        self.arity = 2                  # number of arguments\n",
    "        self.arg_types = [int, int]     # argument types\n",
    "        self.return_type = int          # return type\n",
    "        self.weight = 1                 # weight\n",
    "\n",
    "    def __call__(self, x, y):\n",
    "        return x * y\n",
    "    \n",
    "    def str(x, y):\n",
    "        return f\"{x} * {y}\" \n",
    "\n",
    "class Divide:\n",
    "    '''\n",
    "    Operator to divide two numerical values.\n",
    "    '''\n",
    "    def __init__(self):\n",
    "        self.arity = 2                  # number of arguments\n",
    "        self.arg_types = [int, int]     # argument types\n",
    "        self.return_type = int          # return type\n",
    "        self.weight = 1                 # weight\n",
    "\n",
    "    def __call__(self, x, y):\n",
    "        try: # check for division by zero error\n",
    "            return x / y\n",
    "        except ZeroDivisionError:\n",
    "            return None\n",
    "    \n",
    "    def str(x, y):\n",
    "        return f\"{x} / {y}\"\n",
    "\n",
    "\n",
    "'''\n",
    "GLOBAL CONSTANTS\n",
    "''' \n",
    "\n",
    "# define operators\n",
    "arithmetic_operators = [Add(), Subtract(), Multiply(), Divide()]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "I define a function to extract constants from examples."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def extract_constants(examples):\n",
    "    '''\n",
    "    Extracts the constants from the input-output examples. Also constructs variables as needed\n",
    "    based on the input-output examples, and adds them to the list of constants.\n",
    "    '''\n",
    "\n",
    "    # check validity of provided examples\n",
    "    # if valid, extract arity and argument types\n",
    "    arity, arg_types = check_examples(examples)\n",
    "\n",
    "    # initialize list of constants\n",
    "    constants = []\n",
    "\n",
    "    # get unique set of inputs\n",
    "    inputs = [input for example in examples for input in example[0]]\n",
    "    inputs = set(inputs)\n",
    "\n",
    "    # add 1 to the set of inputs\n",
    "    inputs.add(1)\n",
    "\n",
    "    # extract constants in input\n",
    "    for input in inputs:\n",
    "\n",
    "        if type(input) == int:\n",
    "            constants.append(IntegerConstant(input))\n",
    "        elif type(input) == str:\n",
    "            # constants.append(StringConstant(input))\n",
    "            pass\n",
    "        else:\n",
    "            raise Exception(\"Input of unknown type.\")\n",
    "        \n",
    "    # initialize list of variables\n",
    "    variables = []\n",
    "\n",
    "    # extract variables in input\n",
    "    for position, arg in enumerate(arg_types):\n",
    "        if arg == int:\n",
    "            variables.append(IntegerVariable(position))\n",
    "        elif arg == str:\n",
    "            # variables.append(StringVariable(position))\n",
    "            pass\n",
    "        else:\n",
    "            raise Exception(\"Input of unknown type.\")\n",
    "\n",
    "    return constants + variables"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# initialize program bank\n",
    "program_bank = extract_constants(examples)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "I define a function to determine observational equivalence."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def observationally_equivalent(a, b):\n",
    "    \"\"\"\n",
    "    Returns True if a and b are observationally equivalent, False otherwise.\n",
    "    \"\"\"\n",
    "\n",
    "    pass"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Next, I define the bottom-up synthesis algorithm."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# iterate over each level\n",
    "for i in range(2, max_weight):\n",
    "\n",
    "    # define level program bank\n",
    "    level_program_bank = []\n",
    "\n",
    "    for op in arithmetic_operators:\n",
    "\n",
    "        break"
   ]
  }
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