#!/usr/bin/env python3 # Copyright 2014 Brett Slatkin, Pearson Education Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # Preamble to mimick book environment import logging from pprint import pprint from sys import stdout as STDOUT # Example 1 def my_coroutine(): while True: received = yield print('Received:', received) it = my_coroutine() next(it) # Prime the coroutine it.send('First') it.send('Second') # Example 2 def minimize(): current = yield while True: value = yield current current = min(value, current) # Example 3 it = minimize() next(it) # Prime the generator print(it.send(10)) print(it.send(4)) print(it.send(22)) print(it.send(-1)) # Example 4 ALIVE = '*' EMPTY = '-' # Example 5 from collections import namedtuple Query = namedtuple('Query', ('y', 'x')) # Example 6 def count_neighbors(y, x): n_ = yield Query(y + 1, x + 0) # North ne = yield Query(y + 1, x + 1) # Northeast # Define e_, se, s_, sw, w_, nw ... e_ = yield Query(y + 0, x + 1) # East se = yield Query(y - 1, x + 1) # Southeast s_ = yield Query(y - 1, x + 0) # South sw = yield Query(y - 1, x - 1) # Southwest w_ = yield Query(y + 0, x - 1) # West nw = yield Query(y + 1, x - 1) # Northwest neighbor_states = [n_, ne, e_, se, s_, sw, w_, nw] count = 0 for state in neighbor_states: if state == ALIVE: count += 1 return count # Example 7 it = count_neighbors(10, 5) q1 = next(it) # Get the first query print('First yield: ', q1) q2 = it.send(ALIVE) # Send q1 state, get q2 print('Second yield:', q2) q3 = it.send(ALIVE) # Send q2 state, get q3 print('...') q4 = it.send(EMPTY) q5 = it.send(EMPTY) q6 = it.send(EMPTY) q7 = it.send(EMPTY) q8 = it.send(EMPTY) try: it.send(EMPTY) # Send q8 state, retrieve count except StopIteration as e: print('Count: ', e.value) # Value from return statement # Example 8 Transition = namedtuple('Transition', ('y', 'x', 'state')) # Example 9 def game_logic(state, neighbors): pass def step_cell(y, x): state = yield Query(y, x) neighbors = yield from count_neighbors(y, x) next_state = game_logic(state, neighbors) yield Transition(y, x, next_state) # Example 10 def game_logic(state, neighbors): if state == ALIVE: if neighbors < 2: return EMPTY # Die: Too few elif neighbors > 3: return EMPTY # Die: Too many else: if neighbors == 3: return ALIVE # Regenerate return state # Example 11 it = step_cell(10, 5) q0 = next(it) # Initial location query print('Me: ', q0) q1 = it.send(ALIVE) # Send my status, get neighbor query print('Q1: ', q1) print('...') q2 = it.send(ALIVE) q3 = it.send(ALIVE) q4 = it.send(ALIVE) q5 = it.send(ALIVE) q6 = it.send(EMPTY) q7 = it.send(EMPTY) q8 = it.send(EMPTY) t1 = it.send(EMPTY) # Send for q8, get game decision print('Outcome: ', t1) # Example 12 TICK = object() def simulate(height, width): while True: for y in range(height): for x in range(width): yield from step_cell(y, x) yield TICK # Example 13 class Grid(object): def __init__(self, height, width): self.height = height self.width = width self.rows = [] for _ in range(self.height): self.rows.append([EMPTY] * self.width) def __str__(self): output = '' for row in self.rows: for cell in row: output += cell output += '\n' return output # Example 14 def query(self, y, x): return self.rows[y % self.height][x % self.width] def assign(self, y, x, state): self.rows[y % self.height][x % self.width] = state # Example 15 def live_a_generation(grid, sim): progeny = Grid(grid.height, grid.width) item = next(sim) while item is not TICK: if isinstance(item, Query): state = grid.query(item.y, item.x) item = sim.send(state) else: # Must be a Transition progeny.assign(item.y, item.x, item.state) item = next(sim) return progeny # Example 16 grid = Grid(5, 9) grid.assign(0, 3, ALIVE) grid.assign(1, 4, ALIVE) grid.assign(2, 2, ALIVE) grid.assign(2, 3, ALIVE) grid.assign(2, 4, ALIVE) print(grid) # Example 17 class ColumnPrinter(object): def __init__(self): self.columns = [] def append(self, data): self.columns.append(data) def __str__(self): row_count = 1 for data in self.columns: row_count = max(row_count, len(data.splitlines()) + 1) rows = [''] * row_count for j in range(row_count): for i, data in enumerate(self.columns): line = data.splitlines()[max(0, j - 1)] if j == 0: padding = ' ' * (len(line) // 2) rows[j] += padding + str(i) + padding else: rows[j] += line if (i + 1) < len(self.columns): rows[j] += ' | ' return '\n'.join(rows) columns = ColumnPrinter() sim = simulate(grid.height, grid.width) for i in range(5): columns.append(str(grid)) grid = live_a_generation(grid, sim) print(columns) # Example 20 # This is for the introductory diagram grid = Grid(5, 5) grid.assign(1, 1, ALIVE) grid.assign(2, 2, ALIVE) grid.assign(2, 3, ALIVE) grid.assign(3, 3, ALIVE) columns = ColumnPrinter() sim = simulate(grid.height, grid.width) for i in range(5): columns.append(str(grid)) grid = live_a_generation(grid, sim) print(columns)