class Random: def __init__(self, seed): self.sevenFive = 16807 self.twoThirtyone = 2147483647 self.newNum = seed def next(self): self.newNum = self.sevenFive*self.newNum % self.twoThirtyone return self.newNum def choose(self, limit): return self.next()%limit class Rule: def __init__(self, left, right): self.left = left self.right = right self.count = 1 def __repr__(self): string = str(self.count) string += " " string += str(self.left) string += " -> " for n in range (0, len(self.right)): string += self.right[n] string += " " return string class Grammar: def __init__(self, seed): self.r = Random(seed) self.dictionary = {} def rule(self, left, right): if left not in self.dictionary: self.dictionary[left] = (Rule(left,right),) else: self.dictionary[left] += (Rule(left, right),) def generate(self): if 'Start' in self.dictionary: return self.generating(('Start',)) else: raise RuntimeError def select(self, left): rules = self.dictionary[left] total = 0 c = 0 #Some of the loops are probably not needed for m in range (0, len(rules)): total += rules[m].count index = self.r.choose(total) for c in range (0, len(rules)): index -= rules[c].count if index <= 0: break chosen = rules[c] for n in range (0, len(rules)): if rules[n] is not chosen: rules[n].count += 1 return chosen.right def generating(self,strings): result='' for n in range (0, len(strings)): if strings[n] not in self.dictionary: result += strings[n] result += " " else: result += self.generating(self.select(strings[n])) return result G = Grammar(101) G.rule('Noun', ('cat',)) # 01 G.rule('Noun', ('boy',)) # 02 G.rule('Noun', ('dog',)) # 03 G.rule('Noun', ('girl',)) # 04 G.rule('Verb', ('bit',)) # 05 G.rule('Verb', ('chased',)) # 06 G.rule('Verb', ('kissed',)) # 07 G.rule('Phrase', ('the', 'Noun', 'Verb', 'the', 'Noun')) # 08 G.rule('Story', ('Phrase',)) # 09 G.rule('Story', ('Phrase', 'and', 'Story')) # 10 G.rule('Story', ('Phrase', 'but', 'Story')) # 11 G.rule('Start', ('Story', '.')) # 12 for n in range (0, 5): print(G.generate()) # the cat bit the boy . # the cat kissed the dog and the boy chased the boy . # the cat chased the dog and the girl bit the boy but the girl chased the cat . # the girl chased the dog . # the boy kissed the girl and the cat kissed the girl . print() print() # # J = Grammar(1453) J.rule('Noun', ('sentence',)) J.rule('Noun', ('walrus',)) J.rule('Noun', ('sky',)) J.rule('Noun', ('diamond',)) J.rule('Noun', ('Ottoman Empire',)) J.rule('Verb', ('is',)) J.rule('Verb', ('fanned',)) J.rule('Verb', ('generated',)) J.rule('Verb', ('hit',)) J.rule('Phrase', ('the', 'Noun', 'Verb', 'the', 'Noun')) # 08 J.rule('Phrase', ('Noun', 'Verb', 'the', 'Noun')) J.rule('Story', ('Phrase',)) # 09 J.rule('Story', ('Phrase', 'and', 'Story')) # 10 J.rule('Story', ('Phrase', 'but', 'Story')) # 11 J.rule('Start', ('Story', '.')) # 12 for f in range(0, 5): print(J.generate()) # the walrus is the sentence and the diamond generated the walrus . # the walrus generated the walrus and the walrus generated the sentence but diamond hit the sentence . # sentence fanned the Ottoman Empire . # the sky hit the diamond and sky is the sentence but the sky fanned the diamond . # the walrus generated the diamond and the diamond generated the Ottoman Empire but the sky generated the sentence .