class Assignment(ExpressionAbc):
"""
!!! example
```solidity
x = 1;
y = x = 1;
```
"""
_ast_node: SolcAssignment
_parent: SolidityAbc # TODO: make this more specific
_left_expression: ExpressionAbc
_right_expression: ExpressionAbc
_operator: AssignmentOperator
def __init__(
self, init: IrInitTuple, assignment: SolcAssignment, parent: SolidityAbc
):
super().__init__(init, assignment, parent)
self._operator = assignment.operator
self._left_expression = ExpressionAbc.from_ast(
init, assignment.left_hand_side, self
)
self._right_expression = ExpressionAbc.from_ast(
init, assignment.right_hand_side, self
)
def __iter__(self) -> Iterator[IrAbc]:
yield self
yield from self._left_expression
yield from self._right_expression
@property
def parent(self) -> SolidityAbc:
return self._parent
@property
def left_expression(self) -> ExpressionAbc:
"""
Must be L-value (something that can be assigned to).
Returns:
Left expression of the assignment.
"""
return self._left_expression
@property
def right_expression(self) -> ExpressionAbc:
"""
Returns:
Right expression of the assignment.
"""
return self._right_expression
@property
def operator(self) -> AssignmentOperator:
"""
Returns:
Operator used in the assignment.
"""
return self._operator
@property
@lru_cache(maxsize=2048)
def is_ref_to_state_variable(self) -> bool:
return self.left_expression.is_ref_to_state_variable
@property
@lru_cache(maxsize=2048)
def modifies_state(
self,
) -> Set[Tuple[Union[ExpressionAbc, StatementAbc, YulAbc], ModifiesStateFlag]]:
ret = self.left_expression.modifies_state | self.right_expression.modifies_state
if self.left_expression.is_ref_to_state_variable:
ret |= {(self, ModifiesStateFlag.MODIFIES_STATE_VAR)}
return ret
@property
@lru_cache(maxsize=2048)
def assigned_variables(self) -> Tuple[Optional[Set[AssignedVariablePath]], ...]:
"""
WARNING:
Is not considered stable and so is not exported in the documentation.
"""
def resolve_node(node: ExpressionAbc) -> Set[AssignedVariablePath]:
if isinstance(node, Conditional):
return resolve_node(node.true_expression) | resolve_node(
node.false_expression
)
elif isinstance(node, Identifier):
referenced_declaration = node.referenced_declaration
assert isinstance(referenced_declaration, (DeclarationAbc, SourceUnit))
return {(referenced_declaration,)}
elif isinstance(node, IndexAccess):
return {
path + ("IndexAccess",)
for path in resolve_node(node.base_expression)
}
elif isinstance(node, MemberAccess):
referenced_declaration = node.referenced_declaration
assert isinstance(referenced_declaration, (DeclarationAbc, SourceUnit))
return {
path + (referenced_declaration,)
for path in resolve_node(node.expression)
}
elif isinstance(node, FunctionCall):
function_called = node.function_called
if function_called is None:
return set()
elif isinstance(function_called, (GlobalSymbol, VariableDeclaration)):
# global function or variable getter called
# variable getter may return different type than variable declaration (structs with arrays and mappings)
# return empty set for now
return set()
elif isinstance(function_called, FunctionDefinition):
# cannot be handled in the current implementation, return empty set for now
return set()
elif isinstance(function_called, StructDefinition):
return {(function_called,)}
else:
assert False, f"Unexpected node type: {type(node)}\n{self.source}"
else:
assert False, f"Unexpected node type: {type(node)}\n{self.source}"
node = self.left_expression
if isinstance(node, TupleExpression):
return tuple(
resolve_node(expression) if expression is not None else None
for expression in node.components
)
else:
return (resolve_node(node),)