1.1 --- a/snake.py	Sun Dec 19 23:25:25 2010 +0300
     1.2 +++ b/snake.py	Sun Dec 19 23:26:16 2010 +0300
     1.3 @@ -1,18 +1,36 @@
     1.4 +"""Guts of snakes."""
     1.5 +
     1.6  import engine
     1.7  
     1.8  def preprocess(line):
     1.9 +    """Remove comments and junk spaces from line of snake definition file."""
    1.10      if '//' in line:
    1.11          line = line[:line.index('//')]
    1.12      line = line.rstrip()
    1.13      return line
    1.14  
    1.15  class Snake(object):
    1.16 +    """Snakes.
    1.17 +
    1.18 +    Attributes:
    1.19 +
    1.20 +    - `cells` -- list of cells belonging to the snake The first of these cells
    1.21 +      becomes head, the last one becomes tail, the rest ar body. If snake has
    1.22 +      only one cell, it is tail.
    1.23 +    - `color` -- color of snake
    1.24 +    - `rules` -- a list of Rule objects
    1.25 +    """
    1.26 +
    1.27      def __init__ (self, cells, color):
    1.28          self.cells = cells
    1.29          self.color = color
    1.30          self.rules = []
    1.31  
    1.32      def load (self, file):
    1.33 +        """Load snake description from file.
    1.34 +        
    1.35 +        See program design docs for file syntax.
    1.36 +        """
    1.37          magic, name = preprocess(file.readline()).split(' ', 1)
    1.38          assert magic == "snake", "This is not snake file"
    1.39          while True:
    1.40 @@ -23,6 +41,7 @@
    1.41              self.rules.append(Rule().load(file))
    1.42  
    1.43      def fill (self):
    1.44 +        """Mark every cell in `self.cells` as belonging to self."""
    1.45          for cell in self.cells:
    1.46              cell.snake = self
    1.47          snake.cells[0].type = 'head'
    1.48 @@ -31,6 +50,7 @@
    1.49          return
    1.50  
    1.51  class Rule(object):
    1.52 +    """Rule defining possible behaviour of snake."""
    1.53  
    1.54      codes = {
    1.55          'h': 'head',
    1.56 @@ -47,6 +67,7 @@
    1.57          self.pattern = {}
    1.58  
    1.59      def load (self, file):
    1.60 +        """Load rule definition from file. Ignore any leading empty lines."""
    1.61          y = 0
    1.62          for line in file:
    1.63              line = preprocess(line)
    1.64 @@ -54,13 +75,17 @@
    1.65                  continue
    1.66              if y == 7:
    1.67                  break
    1.68 +            assert len(line) == 8, "Rule lines must be exactly 7 chars long"
    1.69              assert line[-1] == ';', "Rule lines must end with semicolon"
    1.70 -            assert len(line) == 8, "Rule lines must be exactly 7 chars long"
    1.71              for x, char in enumerate(line[:8]):
    1.72                  self.parse_cell(x, y, char)
    1.73              y += 1
    1.74  
    1.75      def parse_cell(self, x, y, char):
    1.76 +        """Parse definition of cell in rule file.
    1.77 +
    1.78 +        Cell is defined by one character.
    1.79 +        """
    1.80          assert char.lower() in self.codes, "Illegal symbol in rule: %s" % char
    1.81          cell = engine.Cell(x, y, None)
    1.82          if char in 'htb':
    1.83 @@ -76,25 +101,24 @@
    1.84          self.pattern[x, y] = cell
    1.85  
    1.86      def applies (self, field, x, y):
    1.87 +        """True if the rule applies in the field at position (x,y)."""
    1.88          for px, fx in zip(range(7), range(x - 3, x + 4)):
    1.89              for py, fy in zip(range(7), range(y - 3, y + 4)):
    1.90 -                pcell = self.pattern[px, py]
    1.91 -                fcell = field.get(fx, fy)
    1.92 -                if pcell.type == 'any':
    1.93 -                    continue
    1.94 -                if pcell.type != fcell.type:
    1.95 -                    return False
    1.96 -                if pcell.snake == 'my' and fcell.snake != self.snake:
    1.97 -                    return False
    1.98 -                elif pcell.snake == 'enemy' and fcell.snake == self.snake:
    1.99 -                    return False
   1.100 +                if fx, fy in field:
   1.101 +                    if field[fx, fy] != self.pattern[px, py]:
   1.102 +                        return False
   1.103 +                else:
   1.104 +                    if self.pattern[px, py].type != 'any':
   1.105 +                        return False
   1.106          return True
   1.107  
   1.108      def rotate (self, rot):
   1.109 +        """Rotate rule pattern `rot` times counterclockwise."""
   1.110          for i in range(((rot % 4) + 4) % 4):
   1.111              self.rotate_ccw()
   1.112  
   1.113      def rotate_ccw(self):
   1.114 +        """Rotate rule pattern one time counterclockwise."""
   1.115          pattern = {}
   1.116          for x in range(7):
   1.117              for y in range(7):