snake: e9c803523da4 snake.py

snake

view 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

line source

1 """Guts of snakes."""

3 import engine

5 def preprocess(line):

6 """Remove comments and junk spaces from line of snake definition file."""

7 if '//' in line:

8 line = line[:line.index('//')]

9 line = line.rstrip()

10 return line

12 class Snake(object):

13 """Snakes.

15 Attributes:

17 - `cells` -- list of cells belonging to the snake The first of these cells

18 becomes head, the last one becomes tail, the rest ar body. If snake has

19 only one cell, it is tail.

20 - `color` -- color of snake

21 - `rules` -- a list of Rule objects

22 """

24 def __init__ (self, cells, color):

25 self.cells = cells

26 self.color = color

27 self.rules = []

29 def load (self, file):

30 """Load snake description from file.

32 See program design docs for file syntax.

33 """

34 for line in file:

35 magic, name = preprocess(line).split(' ', 1)

36 break

37 assert magic == "snake", "This is not snake file"

38 for line in file:

39 line = preprocess(line)

40 if line == 'end':

41 break

42 assert line == '', "Rules must be separated by empty lines"

43 self.rules.append(Rule(self).load(file))

45 def fill (self):

46 """Mark every cell in `self.cells` as belonging to self."""

47 for cell in self.cells:

48 cell.snake = self

49 snake.cells[0].type = 'head'

50 for cell in self.cells[1:-1]:

51 cell.type = 'body'

52 snake.cells[-1].type = 'tail'

53 return

55 class Rule(object):

56 """Rule defining possible behaviour of snake."""

58 codes = {

59 'h': 'head',

60 'b': 'body',

61 't': 'tail',

62 '#': 'wall',

63 ' ': 'any',

64 '-': 'empty',

65 }

67 def __init__ (self, snake):

68 self.snake = snake

69 self.direction = (1, 0)

70 self.pattern = {}

72 def load (self, file):

73 """Load rule definition from file. Ignore any leading empty lines."""

74 y = 0

75 for line in file:

76 line = preprocess(line)

77 if y == 0 and line == '':

78 continue

79 if y == 7:

80 break

81 assert len(line) == 8, "Rule lines must be exactly 7 chars long"

82 assert line[-1] == ';', "Rule lines must end with semicolon"

83 for x, char in enumerate(line[:7]):

84 self.parse_cell(x, y, char)

85 y += 1

87 def parse_cell(self, x, y, char):

88 """Parse definition of cell in rule file.

90 Cell is defined by one character.

91 """

92 assert char.lower() in self.codes, "Illegal symbol in rule: %s" % char

93 cell = engine.Cell(x, y, self.snake)

94 if char in 'htb':

95 if char.islower():

96 cell.snake_type = 'my'

97 else:

98 cell.snake_type = 'enemy'

99 if char == 'h':

100 assert (x, y) == (3, 3), "Own head must in the center of rule"

101 if (x, y) == (3, 3):

102 assert char == 'h', "In the center of rule must be own head"

103 cell.type = self.codes[char.lower()]

104 self.pattern[x, y] = cell

105

106 def applies (self, field, x, y):

107 """True if the rule applies in the field at position (x,y)."""

108 for px, fx in zip(range(7), range(x - 3, x + 4)):

109 for py, fy in zip(range(7), range(y - 3, y + 4)):

110 if (fx, fy) in field:

111 if field[fx, fy] != self.pattern[px, py]:

112 return False

113 else:

114 if self.pattern[px, py].type != 'any':

115 return False

116 return True

117

118 def rotate (self, rot):

119 """Rotate rule pattern `rot` times counterclockwise."""

120 for i in range(((rot % 4) + 4) % 4):

121 self.rotate_ccw()

122

123 def rotate_ccw(self):

124 """Rotate rule pattern one time counterclockwise."""

125 pattern = {}

126 for x in range(7):

127 for y in range(7):

128 pattern[y, 6 - x] = self.pattern[x, y]

129 self.pattern = pattern

130 x, y = self.direction

131 self.direction = y, -x

132

133 # vim: set ts=4 sts=4 sw=4 et: