day19/monstermessages.py

   1 #!/usr/bin/python3
   2
   3 import sys
   4 import re
   5
   6 filename="p1_2.txt"
   7 if len(sys.argv) > 1:
   8     filename=sys.argv[1]
   9
  10 in_rules=True
  11 rules={}
  12 data=[]
  13
  14 for line in open(filename, "r"):
  15     line = line.rstrip()
  16     if line == "":
  17         in_rules=False
  18         continue
  19
  20     if in_rules:
  21         (rule_number,rule) = line.split(":")
  22         rule_number=int(rule_number)
  23         rule=rule.strip()
  24         rules[rule_number] = [s.strip() for s in rule.split("|")]
  25     else:
  26         data.append(line)
  27
  28 def get_rule_regex(rulenumber):
  29     regex=""
  30     first=False
  31     for rule in rules[rulenumber]:
  32         if rule[0] != '"':
  33             # not a character, so we're going to go down the wishing well
  34             for number in rule.split(" "):
  35                 number=int(number)
  36                 regex+=get_rule_regex(number)
  37             regex+="|"
  38         else:
  39             regex+=rule[1:-1]
  40     if regex[-1] == "|":
  41         regex=regex[0:-1]
  42     regex="("+regex+")"
  43
  44     return regex
  45
  46 # ok - so all the rules are in, lets build a huge regex that gets all the rules
  47 for rule_number in rules:
  48     print(str(rule_number) + ": " + "| ".join(rules[rule_number]))
  49
  50 pattern="^"+get_rule_regex(0)+"$"
  51
  52 match_count=0
  53
  54 for line in data:
  55     if re.search(pattern, line):
  56         print("Line: {} matches".format(line))
  57         match_count+=1
  58
  59 print("There were {} matches in total".format(match_count))