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184
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1 import unittest, pprint
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2 from pyyacc import Grammar, Item, EOF
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3
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4
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5 class testLR(unittest.TestCase):
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6 def setUp(self):
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7 pass
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8
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9 def testSimpleGrammar(self):
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10 # 1. define a simple grammar:
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11 g = Grammar(['EOF', 'identifier', '(', ')', '+', '*'])
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12 g.add_production('input', ['expression'])
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13 g.add_production('expression', ['term'])
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14 g.add_production('expression', ['expression', '+', 'term'])
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15 g.add_production('term', ['factor'])
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16 g.add_production('term', ['term', '*', 'factor'])
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17 g.add_production('factor', ['(', 'expression', ')'])
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18 g.add_production('factor', ['identifier'])
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19 g.start_symbol = 'input'
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20 # 2. define input:
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21 tokens = ['identifier', '+', 'identifier', '+', 'identifier', 'EOF']
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22 # 3. build parser:
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23 p = g.genParser()
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24 # 4. feed input:
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25 p.parse(tokens)
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26
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27 class testPG(unittest.TestCase):
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28 """ Tests several parts of the parser generator """
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29 def setUp(self):
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30 g = Grammar(['(', ')'])
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31 g.add_production('goal', ['list'])
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32 g.add_production('list', ['list', 'pair'])
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33 g.add_production('list', ['pair'])
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34 g.add_production('pair', ['(', 'pair', ')'])
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35 g.add_production('pair', ['(', ')'])
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36 g.start_symbol = 'goal'
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37 g.first = g.calcFirstSets()
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38 self.g = g
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39
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40 def testFirstSet(self):
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41 for a in ['(', ')', EOF, 'EPS']:
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42 self.assertEqual(self.g.first[a], {a})
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43 for nt in ['list', 'pair', 'goal']:
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44 self.assertEqual(self.g.first[nt], {'('})
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45
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46 def testInitItemSet(self):
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47 p0, p1, p2, p3, p4 = self.g.productions
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48 s0 = self.g.initialItemSet()
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49 self.assertEqual(len(s0), 9) # 9 with the goal rule included!
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50 self.assertIn(Item(p0, 0, EOF), s0)
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51 self.assertIn(Item(p1, 0, EOF), s0)
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52 self.assertIn(Item(p1, 0, '('), s0)
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53 self.assertIn(Item(p2, 0, EOF), s0)
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54 self.assertIn(Item(p2, 0, '('), s0)
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55 self.assertIn(Item(p3, 0, EOF), s0)
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56 self.assertIn(Item(p3, 0, '('), s0)
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57 self.assertIn(Item(p4, 0, EOF), s0)
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58 self.assertIn(Item(p4, 0, '('), s0)
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59
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60 def testCanonical(self):
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61 s0 = self.g.initialItemSet()
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62 s, gt = self.g.genCanonicalSet(s0)
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63 pprint.pprint(s)
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64 # Must result in 12 sets:
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65 self.assertEqual(len(s), 12)
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66
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67 def testClosure(self):
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68 p0, p1, p2, p3, p4 = self.g.productions
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69 s0 = set()
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70 for p in self.g.productionsForName(self.g.start_symbol):
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71 s0.add(Item(p, 0, EOF))
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72 self.assertEqual(len(s0), 1) # 1 rule
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73 self.assertIn(Item(p0, 0, EOF), s0)
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74
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75 # Invoke closure on set:
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76 s0 = self.g.closure(s0)
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77 self.assertIn(Item(p0, 0, EOF), s0)
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78 self.assertIn(Item(p1, 0, EOF), s0)
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79 self.assertIn(Item(p1, 0, '('), s0)
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80 self.assertIn(Item(p2, 0, EOF), s0)
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81 self.assertIn(Item(p2, 0, '('), s0)
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82 self.assertIn(Item(p3, 0, EOF), s0)
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83 self.assertIn(Item(p3, 0, '('), s0)
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84 self.assertIn(Item(p4, 0, EOF), s0)
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85 self.assertIn(Item(p4, 0, '('), s0)
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86
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87 def testParser(self):
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88 tokens = ['(', '(', ')', '(', ')', ')', 'EOF']
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89 # 3. build parser:
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90 p = self.g.genParser()
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91 # 4. feed input:
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92 p.parse(tokens)
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93
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94 if __name__ == '__main__':
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95 unittest.main()
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96
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97
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