def test_repeated_productions_are_shrunk(self):
""" If two or more productions has the same alpha, they're shrunk.
This implies that if two or more productions has the same alpha, they're
transformed in a single production with all the beta parts of the
productions separated by Or's.
"""
start_symbol = 'expr'
productions = [
grammar.Production(
'expr',
grammar.SingleTerm(str(i))
) for i in range(10)
]
a_grammar = grammar.Grammar(start_symbol, productions)
# The ten productions are transformed in One
self.assertEquals(len(a_grammar.productions), 1)
# The only term of the productions is an Or instance
production = a_grammar.productions[0]
self.assertEquals(start_symbol, production.variable)
self.assertIsInstance(production.term, grammar.Or)
# The Or term contains all the terms in initial productions.
value = production.term.value
for t in value:
self.assertIn(t, [p.term for p in productions])
for t in [p.term for p in productions]:
self.assertIn(t, value)
def test_start_symbol_should_exists_as_variable_in_productions(self):
""" The start symbol must lead at least one of the productions. """
existent_start_symbol = 'existent'
non_existent_start_symbol = 'non_existent'
productions = [
grammar.Production(
existent_start_symbol,
grammar.EpsilonTerminal
) for _ in range(4)
]
# Test OK if start_symbol exists.
grammar.Grammar(
start_symbol=existent_start_symbol,
productions=productions
)
# Test KO if start_symbol_does_not_exists
with self.assertRaises(ValueError):
grammar.Grammar(
start_symbol=non_existent_start_symbol,
productions=productions
)
def test_correct_construction(self):
""" Correct start_symbol and productions lead to a correct grammar. """
base_symbol = 't'
start_symbol = base_symbol + '0'
productions = [
grammar.Production(
base_symbol + str(i),
grammar.EpsilonTerminal
) for i in range(4)
]
a_grammar = grammar.Grammar(
start_symbol=start_symbol,
productions=productions
)
self.assertEquals(start_symbol, a_grammar.start_symbol)
for production in productions:
self.assertIn(production, a_grammar.productions)
for production in a_grammar.productions:
self.assertIn(production, productions)
def test_productions_should_be_an_list_of_production_instances(self):
""" Productions should be a list of Production instances. """
all_but_one = [
grammar.Production(
't',
grammar.EpsilonTerminal
) for _ in range(4)
]
all_but_one.append(grammar.EpsilonTerminal)
for invalid_productions in (
(),
{},
None,
'terminal',
['terminal'],
grammar.EpsilonTerminal,
[grammar.EpsilonTerminal],
all_but_one,
):
with self.assertRaises(ValueError):
grammar.Grammar('terminal', invalid_productions)
awesome_grammar = grammar.Grammar(
start_symbol='frase',
productions=[
grammar.Production(
'frase',
grammar.And(
grammar.Multiplier('sujeto', upper=1), 'predicado',
grammar.Multiplier(
grammar.And('conjuncion',
grammar.Multiplier('sujeto', upper=1),
'predicado'), )),
),
grammar.Production('conjuncion', grammar.Or(('y', 4), ('o', 6))),
grammar.Production('sujeto', grammar.Or('sujeto_masc', 'sujeto_fem')),
grammar.Production(
'sujeto_masc',
grammar.Or(
grammar.And('el', 'nombre_comun_masc'),
grammar.And(grammar.Multiplier('el', upper=1),
'nombre_propio_masc'),
)),
grammar.Production(
'sujeto_fem',
grammar.Or(
grammar.And('la', 'nombre_comun_fem'),
grammar.And(grammar.Multiplier('la', upper=1),
'nombre_propio_fem'),
)),
grammar.Production(
'nombre_comun_masc',
grammar.Or('chico', 'chatarrero', 'profesor', 'mutante', 'zombie'),
),
grammar.Production(
'nombre_propio_masc',
grammar.Or('Pepe', 'Paco Pil', 'Richal'),
),
grammar.Production(
'nombre_comun_fem',
grammar.Or('camionera', 'guitarrista', 'prestituta', 'tabernera'),
),
grammar.Production(
'nombre_propio_fem',
grammar.Or('Juani', 'Pepi', 'Lili'),
),
grammar.Production(
'predicado',
grammar.And('verbo', grammar.Multiplier('complemento', upper=1))),
grammar.Production(
'verbo',
grammar.Or(
'corre',
'habla',
'ríe',
'tiene',
'va',
'come',
'dice',
'canta',
'caga',
'mea',
'micciona',
'excreta',
'evacúa',
)),
grammar.Production(
'complemento',
grammar.Or(
'la comida',
'como puede',
'que se las pela',
'soy una rumbera',
'abriendo puertas',
'a las barricadas',
'algo',
'siempre',
'a dos manos',
)),
])