def substitute_hole_in_expression(self, expression, pairs):
"""
Expression is a z3 expression, and pairs is a list of pairs
of the form (function declaration representing hole, substitute)
For now substitute can only be a value.
TODO: change this so substitute can be a conditional expression as well.
The latter will require to introduce a 'table variable'.
"""
assert z3p.is_expr(expression)
holes = [pair[0] for pair in pairs]
if z3p.is_bool_or_int_value(expression):
return expression
if z3p.is_app(expression):
declaration = expression.decl()
for hole, substitute in pairs:
if declaration == hole:
input_variables = [expression.arg(i)
for i in range(expression.num_args())]
conditional = constraint_model.lookup_table_to_conditional_expression(substitute, input_variables)
# introduce table variable and add table declaration in tables
table_id = len(self.tables.keys())
table_var_name = 'table_{}'.format(table_id)
self.tables[table_var_name] = conditional
return z3p.Const(table_var_name, hole.range())
if expression.num_args() == 2:
expression1 = self.substitute_hole_in_expression(expression.arg(0), pairs)
expression2 = self.substitute_hole_in_expression(expression.arg(1), pairs)
operator = expression.decl()
return operator(expression1, expression2)
return expression
def z3_to_python_value(value):
"""
is_expr: Return `True` if `a` is a Z3 expression, is_expr(1) is False
"""
assert z3p.is_expr(value)
if z3p.is_int_value(value):
return value.as_long()
elif value.sort() == z3p.BoolSort():
if z3p.is_true(value):
return True
elif z3p.is_false(value):
return False
raise NotImplementedError
def z3_to_python_value(value):
"""
is_expr: Return `True` if `a` is a Z3 expression, is_expr(1) is False
"""
assert z3p.is_expr(value)
if z3p.is_int_value(value):
return value.as_long()
elif value.sort() == z3p.BoolSort():
if z3p.is_true(value):
return True
elif z3p.is_false(value):
return False
raise NotImplementedError
