def _get_grammar_1(self):
grammar = Grammar()
grammar.parse("""
Number -> Integer
| Real
Integer -> Digit
| Integer Digit
Real -> Integer Fraction Scale
Fraction -> . Integer
Scale -> e Sign Integer
| Empty
Digit -> 0
| 1
| 2
| 3
| 4
| 5
| 6
| 7
| 8
| 9
Sign -> +
| -
Empty -> ε
""")
return grammar
def test_chomsky_normal_form_case_1(self):
grammar = Grammar()
grammar.parse("""
Number -> Integer | Real
Integer -> Digit | Integer Digit
Real -> Integer Fraction Scale
Fraction -> . Integer
Scale -> e Sign Integer | Empty
Digit -> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
Sign -> + | -
Empty -> ε
""")
grammar = to_chomsky_normal_form(grammar)
self.assertEqual(
str(grammar), """
Number -> 0
| 1
| 2
| 3
| 4
| 5
| 6
| 7
| 8
| 9
| Integer Digit
| Integer Fraction
| N_1 Scale_1
Integer -> 0
| 1
| 2
| 3
| 4
| 5
| 6
| 7
| 8
| 9
| Integer Digit
Fraction -> T_1 Integer
Digit -> 0
| 1
| 2
| 3
| 4
| 5
| 6
| 7
| 8
| 9
Sign -> +
| -
Scale_1 -> N_2 Integer
N_1 -> Integer Fraction
T_1 -> .
T_2 -> e
N_2 -> T_2 Sign
"""[1:])
def test_case_2(self):
grammar = Grammar()
grammar.parse("""
S -> L S D | ε
L -> ε
D -> d
""")
result = parse_with_unger(grammar, 'd')
self.assertEqual(result, ('L S D', ('ε', 'ε'), ('ε', 'ε'), ('d', 'd')))
def test_eliminate_unit_rules_case_1(self):
grammar = Grammar()
grammar.parse("""
Number -> Integer | Real
Integer -> Digit | Integer Digit
Real -> Integer Fraction Scale
Fraction -> . Integer
Scale -> e Sign Integer | Empty
Digit -> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
Sign -> + | -
Empty -> ε
""")
grammar = eliminate_epsilon_rules(grammar)
grammar = eliminate_unit_rules(grammar)
self.assertEqual(
str(grammar), """
Number -> 0
| 1
| 2
| 3
| 4
| 5
| 6
| 7
| 8
| 9
| Integer Digit
| Integer Fraction
| Integer Fraction Scale_1
Integer -> 0
| 1
| 2
| 3
| 4
| 5
| 6
| 7
| 8
| 9
| Integer Digit
Fraction -> . Integer
Digit -> 0
| 1
| 2
| 3
| 4
| 5
| 6
| 7
| 8
| 9
Sign -> +
| -
Real_1 -> Integer Fraction
| Integer Fraction Scale_1
Scale_1 -> e Sign Integer
"""[1:])
def test_parse_case_1(self):
grammar = Grammar()
grammar.parse('S -> A B C | D E | F')
grammar = str(grammar)
self.assertEqual(grammar, """
S -> A B C
| D E
| F
"""[1:])
def test_eliminate_epsilon_rules_case_3(self):
grammar = Grammar()
grammar.parse("""
S -> L M
L -> ε
M -> ε
""")
grammar = eliminate_epsilon_rules(grammar)
self.assertEqual(str(grammar), """
S_1 -> ε
"""[1:])
def test_parse_case_3(self):
grammar = Grammar()
grammar.parse("""
S -> A B C
S -> D E
S -> F
""")
grammar = str(grammar)
self.assertEqual(grammar, """
S -> A B C
| D E
| F
"""[1:])
def test_eliminate_unit_rules_case_3(self):
grammar = Grammar()
grammar.parse("""
S -> A
A -> A | a
""")
grammar = eliminate_epsilon_rules(grammar)
grammar = eliminate_unit_rules(grammar)
self.assertEqual(str(grammar), """
S -> A
| a
A -> A
| a
"""[1:])
def test_case_1(self):
grammar = Grammar()
grammar.parse("""
Expr -> Expr + Term | Term
Term -> Term × Factor | Factor
Factor -> ( Expr ) | i
""")
result = parse_with_unger(grammar, '(i+i)×i')
self.assertEqual(result,
('Term', ('Term × Factor',
('Factor',
('( Expr )', '(',
('Expr + Term',
('Term', ('Factor', ('i', 'i'))), '+',
('Factor',
('i', 'i'))), ')')), '×', ('i', 'i'))))
def test_chomsky_normal_form_case_2(self):
grammar = Grammar()
grammar.parse("""
S -> A B C D
A -> B C D | a b c d
B -> C D | b c d
C -> C D | c d
D -> E H I | d
E -> F G
F -> F
G -> G
H -> B C D
I -> i
""")
grammar = to_chomsky_normal_form(grammar)
self.assertEqual(
str(grammar), """
S -> N_2 D
A -> N_3 D
| N_5 T_4
B -> C D
| N_6 T_4
C -> C D
| T_3 T_4
D -> N_7 I
| d
E -> F G
F -> F
G -> G
H -> N_3 D
I -> i
N_1 -> A B
N_2 -> N_1 C
N_3 -> B C
T_1 -> a
T_2 -> b
N_4 -> T_1 T_2
T_3 -> c
N_5 -> N_4 T_3
T_4 -> d
N_6 -> T_2 T_3
N_7 -> E H
"""[1:])
def test_eliminate_epsilon_rules_case_1(self):
grammar = Grammar()
grammar.parse("""
S -> L a M
L -> L M
L -> ε
M -> M M
M -> ε
""")
grammar = eliminate_epsilon_rules(grammar)
self.assertEqual(
str(grammar), """
S_1 -> a
| L_1 a
| a M_1
| L_1 a M_1
L_1 -> L_1
| M_1
| L_1 M_1
M_1 -> M_1
| M_1 M_1
"""[1:])
def test_eliminate_unit_rules_case_2(self):
grammar = Grammar()
grammar.parse("""
S -> A
A -> B
B -> C
C -> D
D -> E
E -> F
F -> a
""")
grammar = eliminate_epsilon_rules(grammar)
grammar = eliminate_unit_rules(grammar)
self.assertEqual(
str(grammar), """
S -> a
A -> a
B -> a
C -> a
D -> a
E -> a
F -> a
"""[1:])
def test_case_4(self):
grammar = Grammar()
grammar.init_min_length()
grammar.parse("""
S -> A B
A -> a b
B -> c
""")
result = parse_with_unger(grammar, 'abc')
self.assertEqual(result, ('A B', ('a b', 'a', 'b'), ('c', 'c')))
def test_parse_case_4(self):
grammar = Grammar()
grammar.parse("""
Number -> Integer | Real
Integer -> Digit | Integer Digit
Real -> Integer Fraction Scale
Fraction -> . Integer
Scale -> e Sign Integer | Empty
Digit -> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
Sign -> + | -
Empty -> ε
""")
self.assertTrue(grammar.is_terminal('e'))
self.assertTrue(grammar.is_terminal('ε'))
self.assertTrue(grammar.is_non_terminal('Sign'))
grammar.init_nullable()
grammar = str(grammar)
self.assertEqual(
grammar, """
Number -> Integer
| Real
Integer -> Digit
| Integer Digit
Real -> Integer Fraction Scale
Fraction -> . Integer
Scale -> e Sign Integer
| Empty
Digit -> 0
| 1
| 2
| 3
| 4
| 5
| 6
| 7
| 8
| 9
Sign -> +
| -
Empty -> ε
"""[1:])
def test_grammar_min_length(self):
grammar = Grammar()
grammar.parse("""
Number -> Integer | Real
Integer -> Digit | Integer Digit
Real -> Integer Fraction Scale
Fraction -> . Integer
Scale -> e Sign Integer | Empty
Digit -> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
Sign -> + | -
Empty -> ε
""")
grammar.init_min_length()
self.assertEqual(0, grammar.symbols['Scale'].min_length)
self.assertEqual(1, grammar.symbols['Number'].min_length)
self.assertEqual(2, grammar.symbols['Fraction'].min_length)
self.assertEqual(3, grammar.symbols['Real'].min_length)
def test_parse_error_case_head(self):
grammar = Grammar()
with self.assertRaises(RuntimeError):
grammar.parse('S S -> A B C | D E | F')
def test_parse_error_case_empty_all(self):
grammar = Grammar()
with self.assertRaises(RuntimeError):
grammar.parse('S ->')