File: class/Extras/Code/Text/rules.py

from string import split, join, strip
def internal_rule(string): 
 i = split(string, ' if ') 
 t = split(i[1], ' then ') 
 r = split(i[0], 'rule ') 
 return {'rule':strip(r[1]), 'if':internal(t[0]), 'then':internal(t[1])}
def external_rule(rule):
 return ('rule ' + rule['rule'] + 
 ' if ' + external(rule['if']) + 
 ' then ' + external(rule['then']) + '.')
def internal(conjunct):
 res = [] # 'a b, c d'
 for clause in split(conjunct, ','): # -> ['a b', ' c d']
 res.append(split(clause)) # -> [['a','b'], ['c','d']]
 return res
def external(conjunct): 
 strs = []
 for clause in conjunct: # [['a','b'], ['c','d']] 
 strs.append(join(clause)) # -> ['a b', 'c d'] 
 return join(strs, ', ') # -> 'a b, c d'