def is_type4(grammar):
"""
FC(Finite Choice) grammar
all right-sides contains only terminals
"""
assert is_grammar(grammar)
rules, _ = grammar
for rule in rules:
for symbol in rule[1]:
if not is_terminal(symbol):
return False
return True
def is_type2(grammar):
"""
CF(Context Free) grammar
All rules whose left-side only contains one non-terminal and without any terminal
"""
assert is_grammar(grammar)
rules, _ = grammar
for rule in rules:
left_side, right_side = rule
if len(left_side) > 1:
return False
return True
def is_type1(grammar):
"""
CS(Context Sensitive) grammar
As CS grammar is equavalent to Monotonic grammar, the later is implemented
"""
assert is_grammar(grammar)
rules, _ = grammar
for rule in rules:
left_side, right_side = rule
if len(left_side) > len(right_side):
return False
return True
def is_type0(grammar):
"""
PS(Phrase Structure) grammar, formal grammar without any limit
"""
assert is_grammar(grammar)
return True
def is_type4(grammar):
"""
FC(Finite Choice) grammar
all right-sides contains only terminals
"""
assert is_grammar(grammar)
rules, _ = grammar
for rule in rules:
for symbol in rule[1]:
if not is_terminal(symbol):
return False
return True
if __name__ == '__main__':
import grammars as gs
assert is_grammar(gs.g1)
assert is_type0(gs.g1)
assert not is_type1(gs.g1)
assert is_type0(gs.g2)
assert is_type1(gs.g2)
assert not is_type2(gs.g2)
assert is_type2(gs.g3)
assert not is_type3(gs.g3)