def visit_class_stmt(self, stmt: Class) -> object:
environment = self.env
superclass = None
if stmt.superclass:
superclass = self.evaluate(stmt.superclass)
if not isinstance(superclass, LoxClass):
msg = "Superclass must be a class."
raise PloxRuntimeError(stmt.superclass.name, msg)
environment.define(stmt.name.lexeme, None)
if stmt.superclass:
environment = Environment(environment)
environment.define('super', superclass)
methods = {}
for method in stmt.methods:
is_initializer = method.name.lexeme == 'init'
is_getter = method.getter
function = LoxFunction(method, environment, is_initializer,
is_getter)
methods[method.name.lexeme] = function
klass = LoxClass(stmt.name.lexeme, superclass, methods)
if superclass:
environment = environment.enclosing
environment.assign(stmt.name, klass)
return None
def call(self, interpreter, arguments):
environment = Environment(self.closure)
for param, arg in zip(self.declaration.params, arguments):
environment.define(param.lexeme, None)
environment.assign(param, arg)
try:
interpreter._execute_block(self.declaration.body, environment)
except PloxReturnException as return_value:
if self.is_initializer:
return self.closure.get_at(0, 'this')
return return_value.value
if self.is_initializer:
return self.closure.get_at(0, "this")
return None