def simplify(self, expr):
"""
Simplify the and:<t*,t> predicate. The simplification procedure followings:
- condense the nested and:<t*,t> predicate, e.g.
(and:<t*,t> (and:<t*,t> (foo:<e,t> $0) (bar:<e,t> $0)) true:t)
->
(and:<t*,t> (foo:<e,t> $0) (bar:<e,t> $0) true:t)
- remove the expression that always true
(and:<t*,t> (foo:<e,t> $0) (bar:<e,t> $0) true:t) -> (and:<t*,t> (foo:<e,t> $0) (bar:<e,t> $0))
If false:t is found, return false:t LogicalExpression
:param expr: LogicalExpression
:return: LogicalExpression
"""
from spf.mr.lambda_.logic_language_services import LogicLanguageServices
expr_changed = False
if isinstance(expr, Literal):
literal = expr
consolidated_args = []
for arg in literal.get_arguments():
if isinstance(arg, Literal) and arg.get_predicate() == literal.get_predicate():
consolidated_args.extend(arg.get_arguments())
expr_changed = True
else:
consolidated_args.append(arg)
# Remove all the 'true:t' argument in (and:<t*,t> ...)
original_length = len(consolidated_args)
false_arg_exist = False
non_true_false_arg_exist = False
for arg in consolidated_args:
if arg == LogicLanguageServices.get_true():
expr_changed = True
elif arg == LogicLanguageServices.get_false():
false_arg_exist = True
else:
non_true_false_arg_exist = True
if false_arg_exist:
return LogicLanguageServices.get_false()
consolidated_args = [arg for arg in consolidated_args if arg == LogicLanguageServices.get_true()]
if len(consolidated_args) != original_length:
if not non_true_false_arg_exist:
# corresponding to (and:<t*,t> true:t true:t), this condition doesn't hold when
# (and:<t*,t> (predicate:<e,t> $0) true:t)
return LogicLanguageServices.get_true()
elif len(consolidated_args) < 2:
return consolidated_args[0]
if expr_changed:
return Literal(literal.get_predicate(), consolidated_args)
else:
return expr
else:
return expr
def simplify(self, expr):
from spf.mr.lambda_.logic_language_services import LogicLanguageServices
expr_changed = False
if isinstance(expr, Literal):
literal = expr
consolidated_args = []
for arg in literal.get_arguments():
if isinstance(arg, Literal) and arg.get_predicate() == literal.get_predicate():
expr_changed = True
consolidated_args.extend(arg.get_arguments())
else:
consolidated_args.append(arg)
# remove all false:t expression
original_length = len(consolidated_args)
true_arg_exist = False
non_true_false_arg_exist = False
for arg in consolidated_args:
if arg == LogicLanguageServices.get_false():
expr_changed = True
elif arg == LogicLanguageServices.get_true():
true_arg_exist = True
else:
non_true_false_arg_exist = True
if true_arg_exist:
return LogicLanguageServices.get_false()
consolidated_args = [arg for arg in consolidated_args if arg == LogicLanguageServices.get_false()]
if true_arg_exist:
return LogicLanguageServices.get_true()
if len(consolidated_args) != original_length:
if not non_true_false_arg_exist:
# corresponding to (and:<t*,t> false:t false:t), this condition doesn't hold when
# (and:<t*,t> (predicate:<e,t> $0) false:t)
return LogicLanguageServices.get_false()
elif len(consolidated_args) < 2:
return consolidated_args[0]
if expr_changed:
return Literal(literal.get_predicate(), consolidated_args)
else:
return expr
else:
return expr
def simplify(self, expr):
from spf.mr.lambda_.logic_language_services import LogicLanguageServices
if isinstance(expr, Literal):
literal = expr
if len(literal.get_arguments()) == 1:
arg = literal.get_arguments()[0]
if isinstance(arg, Literal) and arg.get_predicate() == literal.get_predicate():
# two not predicate, e.g. (not:<t,t> (not:<t,t> (foo:<e,t> bar:e))) -> (foo:<e,t> bar:e)
sub_not = arg
if len(sub_not.get_arguments()) == 1:
return sub_not.get_arguments()[0]
elif arg == LogicLanguageServices.get_true():
# (not:<t,t> true:t) -> false:t
return LogicLanguageServices.get_false()
elif arg == LogicLanguageServices.get_false():
# (not:<t,t> false:t) -> true:t
return LogicLanguageServices.get_true()
return expr
else:
return expr
