snake: snake.py annotate

snake

annotate snake.py @ 65:e9c803523da4

snake load methods: Python complains about mixing iterators & methods on file object; fixed that

author	Danya Alexeyevsky <me.dendik@gmail.com>
date	Mon, 20 Dec 2010 00:33:24 +0300
parents	27a43636ab6e
children	2d4b7e24d914

rev	line source
me@44	1 """Guts of snakes."""
me@44	2
me@34	3 import engine
me@34	4
me@34	5 def preprocess(line):
me@44	6 """Remove comments and junk spaces from line of snake definition file."""
me@34	7 if '//' in line:
me@34	8 line = line[:line.index('//')]
me@34	9 line = line.rstrip()
me@34	10 return line
martiran@30	11
martiran@30	12 class Snake(object):
me@44	13 """Snakes.
me@44	14
me@44	15 Attributes:
me@44	16
me@44	17 - `cells` -- list of cells belonging to the snake The first of these cells
me@44	18 becomes head, the last one becomes tail, the rest ar body. If snake has
me@44	19 only one cell, it is tail.
me@44	20 - `color` -- color of snake
me@44	21 - `rules` -- a list of Rule objects
me@44	22 """
me@44	23
martiran@32	24 def __init__ (self, cells, color):
martiran@32	25 self.cells = cells
martiran@32	26 self.color = color
martiran@32	27 self.rules = []
me@34	28
me@34	29 def load (self, file):
me@44	30 """Load snake description from file.
me@44	31
me@44	32 See program design docs for file syntax.
me@44	33 """
me@65	34 for line in file:
me@65	35 magic, name = preprocess(line).split(' ', 1)
me@65	36 break
me@34	37 assert magic == "snake", "This is not snake file"
me@65	38 for line in file:
me@65	39 line = preprocess(line)
me@34	40 if line == 'end':
me@34	41 break
me@34	42 assert line == '', "Rules must be separated by empty lines"
me@51	43 self.rules.append(Rule(self).load(file))
me@34	44
martiran@30	45 def fill (self):
me@44	46 """Mark every cell in `self.cells` as belonging to self."""
martiran@32	47 for cell in self.cells:
martiran@32	48 cell.snake = self
martiran@31	49 snake.cells[0].type = 'head'
me@45	50 for cell in self.cells[1:-1]:
me@45	51 cell.type = 'body'
martiran@31	52 snake.cells[-1].type = 'tail'
martiran@31	53 return
me@34	54
martiran@30	55 class Rule(object):
me@44	56 """Rule defining possible behaviour of snake."""
me@34	57
me@34	58 codes = {
me@34	59 'h': 'head',
me@34	60 'b': 'body',
me@34	61 't': 'tail',
me@34	62 '#': 'wall',
me@34	63 ' ': 'any',
me@34	64 '-': 'empty',
me@34	65 }
me@34	66
martiran@32	67 def __init__ (self, snake):
martiran@32	68 self.snake = snake
me@34	69 self.direction = (1, 0)
me@34	70 self.pattern = {}
me@34	71
me@34	72 def load (self, file):
me@44	73 """Load rule definition from file. Ignore any leading empty lines."""
me@34	74 y = 0
me@34	75 for line in file:
me@34	76 line = preprocess(line)
me@34	77 if y == 0 and line == '':
me@34	78 continue
me@36	79 if y == 7:
me@36	80 break
me@41	81 assert len(line) == 8, "Rule lines must be exactly 7 chars long"
me@34	82 assert line[-1] == ';', "Rule lines must end with semicolon"
me@63	83 for x, char in enumerate(line[:7]):
me@34	84 self.parse_cell(x, y, char)
me@34	85 y += 1
me@34	86
me@34	87 def parse_cell(self, x, y, char):
me@44	88 """Parse definition of cell in rule file.
me@44	89
me@44	90 Cell is defined by one character.
me@44	91 """
me@34	92 assert char.lower() in self.codes, "Illegal symbol in rule: %s" % char
me@51	93 cell = engine.Cell(x, y, self.snake)
me@34	94 if char in 'htb':
me@34	95 if char.islower():
me@51	96 cell.snake_type = 'my'
me@34	97 else:
me@51	98 cell.snake_type = 'enemy'
me@37	99 if char == 'h':
me@37	100 assert (x, y) == (3, 3), "Own head must in the center of rule"
me@37	101 if (x, y) == (3, 3):
me@37	102 assert char == 'h', "In the center of rule must be own head"
me@34	103 cell.type = self.codes[char.lower()]
me@34	104 self.pattern[x, y] = cell
me@34	105
martiran@32	106 def applies (self, field, x, y):
me@44	107 """True if the rule applies in the field at position (x,y)."""
me@38	108 for px, fx in zip(range(7), range(x - 3, x + 4)):
me@38	109 for py, fy in zip(range(7), range(y - 3, y + 4)):
me@49	110 if (fx, fy) in field:
me@43	111 if field[fx, fy] != self.pattern[px, py]:
me@43	112 return False
me@43	113 else:
me@43	114 if self.pattern[px, py].type != 'any':
me@43	115 return False
me@38	116 return True
me@34	117
martiran@32	118 def rotate (self, rot):
me@44	119 """Rotate rule pattern `rot` times counterclockwise."""
me@39	120 for i in range(((rot % 4) + 4) % 4):
me@39	121 self.rotate_ccw()
me@39	122
me@39	123 def rotate_ccw(self):
me@44	124 """Rotate rule pattern one time counterclockwise."""
me@39	125 pattern = {}
me@39	126 for x in range(7):
me@39	127 for y in range(7):
me@39	128 pattern[y, 6 - x] = self.pattern[x, y]
me@39	129 self.pattern = pattern
me@39	130 x, y = self.direction
me@39	131 self.direction = y, -x
me@34	132
me@34	133 # vim: set ts=4 sts=4 sw=4 et: