Visualizer for map skeleton

gistfile1.py

#!/usr/bin/python

import re
import sys

road_vertex = re.compile("road_vertex\(([\w\d]+),([\w\d]+),([\w\d]+),([\w\d]+),([\w\d]+)\)")

def display_maze(facts):
  """turn a list of ansprolog facts into a nice ascii-art maze diagram"""
  max_x = 1
  max_y = 1
  solid = {}
  vertices = {}
  connects = {}

  for fact in facts:
    m = road_vertex.match(fact)
    if m:
      n1, n2, i, x, y = m.groups()
      n1, n2, i, x, y = int(n1), int(n2), int(i), int(x), int(y)
      pos = (x,y)
      conn = (n1,n2,i)
      max_x, max_y = max(x, max_x), max(y, max_y)
      vertices[conn] = pos
      connects[(n1,n2)] = True

  for (n1,n2) in connects:
    i = 0
    k0 = (n1,n2,i)
    k1 = (n1,n2,i+1)
    while k1 in vertices:
      x0,y0 = vertices[k0] 
      x1,y1 = vertices[k1]
      if x0 == x1:
        minY = min(y0,y1)
        maxY = max(y0,y1)
        for y in range(minY,maxY+1):
          pos = (x0,y)
          solid[pos] = True
      else:
        minX = min(x0,x1)
        maxX = max(x0,x1)
        for x in range(minX,maxX+1):
          pos = (x,y0)
          solid[pos] = True
      i = i+1
      k0 = (n1,n2,i)
      k1 = (n1,n2,i+1)

  def code(x,y):
    """decide how a maze cell should be tpyeset"""
    pos = (x,y)
    if pos in solid:
      return " @ "
    else:
      return " . "

  for y in range(0,max_y+1):
    print "".join([code(x,y) for x in range(0,max_x+1)])

def main():
  """look for lines that contain logical facts and try to turn each of those
  into a maze"""
  for line in sys.stdin.xreadlines():
    line = line.strip()
    if line:
      if line[0].islower():
        facts = line.split(' ')
        display_maze(facts)
      else:
        print "% " + line

if __name__ == "__main__":
  main()