Mercurial > lcfOS

comparison python/testpyy.py @ 192:6cd6260789a1

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Added more tests for parser generator
author Windel Bouwman
date Sun, 26 May 2013 23:19:27 +0200
parents 6b2bec5653f1
children b01429a5d695
comparison
equal deleted inserted replaced
191:6b2bec5653f1 192:6cd6260789a1
1 import unittest, pprint 1 import unittest, pprint
2 from pyyacc import Grammar, Item, EOF 2 from pyyacc import Grammar, Item, EOF, ParserGenerationException
3 from ppci import Token 3 from ppci import Token
4 4
5 def genTokens(lst): 5 def genTokens(lst):
6 for t in lst: 6 for t in lst:
7 yield Token(t, t, 0) 7 yield Token(t, t, 0)
25 tokens = genTokens(['identifier', '+', 'identifier', '+', 'identifier']) 25 tokens = genTokens(['identifier', '+', 'identifier', '+', 'identifier'])
26 # 3. build parser: 26 # 3. build parser:
27 p = g.genParser() 27 p = g.genParser()
28 # 4. feed input: 28 # 4. feed input:
29 p.parse(tokens) 29 p.parse(tokens)
30 def testReduceReduceConflict(self):
31 """ Check if a reduce-reduce conflict is detected """
32 # Define a grammar with an obvious reduce-reduce conflict:
33 g = Grammar([EOF, 'id'])
34 g.add_production('goal', ['a'])
35 g.add_production('a', ['b'])
36 g.add_production('a', ['c'])
37 g.add_production('b', ['id'])
38 g.add_production('c', ['id'])
39 g.start_symbol = 'goal'
40 with self.assertRaises(ParserGenerationException):
41 p = g.genParser()
42 def testShiftReduceConflict(self):
43 g = Grammar([EOF, 'if', 'then', 'else'])
44 g.add_production('if_stmt', ['if', 'then'])
45 g.add_production('if_stmt', ['if', 'then', 'else'])
46 g.add_production('stmt', ['if_stmt', 'else'])
47 g.start_symbol = 'stmt'
48 with self.assertRaises(ParserGenerationException):
49 g.genParser()
50 def testUndefinedTerminal(self):
51 """ Test correct behavior when a terminal is undefined """
52 g = Grammar([EOF, 'b'])
53 g.add_production('goal', ['a'])
54 g.add_production('a', ['b'])
55 g.add_production('a', ['c'])
56 g.start_symbol = 'goal'
57 with self.assertRaises(ParserGenerationException):
58 g.genParser()
59 def testRedefineTerminal(self):
60 """ Test correct behavior when a terminal is redefined """
61 g = Grammar([EOF, 'b', 'c'])
62 g.add_production('goal', ['a'])
63 with self.assertRaises(ParserGenerationException):
64 g.add_production('b', ['c']) # Not allowed
65 g.add_production('a', ['c'])
66 g.start_symbol = 'goal'
67 g.genParser()
30 68
31 class testExpressionGrammar(unittest.TestCase): 69 class testExpressionGrammar(unittest.TestCase):
32 def setUp(self): 70 def setUp(self):
33 g = Grammar(['EOF', 'identifier', '(', ')', '+', '*', 'num']) 71 g = Grammar(['EOF', 'identifier', '(', ')', '+', '*', 'num'])
34 g.add_production('input', ['expression']) 72 g.add_production('input', ['expression'])