wake.ir.meta.try_catch_clause module

TryCatchClause class

Bases: SolidityAbc

Example

All the following are try/catch clauses in the example below:

• returns(uint x) {},
• catch Error(string memory reason) {},
• catch Panic(uint errorCode) {},
• catch (bytes memory lowLevelData) {}.

contract C {
    function foo() public view {
        try this.bar(10) returns(uint x) {}
        catch Error(string memory reason) {}
        catch Panic(uint errorCode) {}
        catch (bytes memory lowLevelData) {}
    }

    function bar(uint x) external pure returns(uint) {
        return x;
    }
}

Source code in wake/ir/meta/try_catch_clause.py

class TryCatchClause(SolidityAbc):
    """
    !!! example
        All the following are try/catch clauses in the example below:

        - `:::solidity returns(uint x) {}`,
        - `:::solidity catch Error(string memory reason) {}`,
        - `:::solidity catch Panic(uint errorCode) {}`,
        - `:::solidity catch (bytes memory lowLevelData) {}`.

        ```solidity
        contract C {
            function foo() public view {
                try this.bar(10) returns(uint x) {}
                catch Error(string memory reason) {}
                catch Panic(uint errorCode) {}
                catch (bytes memory lowLevelData) {}
            }

            function bar(uint x) external pure returns(uint) {
                return x;
            }
        }
        ```
    """

    _ast_node: SolcTryCatchClause
    _parent: TryStatement

    _block: Block
    _error_name: str
    _parameters: Optional[ParameterList]

    def __init__(
        self,
        init: IrInitTuple,
        try_catch_clause: SolcTryCatchClause,
        parent: TryStatement,
    ):
        super().__init__(init, try_catch_clause, parent)
        self._block = Block(init, try_catch_clause.block, self)
        self._error_name = try_catch_clause.error_name

        if try_catch_clause.parameters is None:
            self._parameters = None
        else:
            self._parameters = ParameterList(init, try_catch_clause.parameters, self)

    def __iter__(self) -> Iterator[IrAbc]:
        yield self
        yield from self._block
        if self._parameters is not None:
            yield from self._parameters

    @property
    def parent(self) -> TryStatement:
        """
        Returns:
            Parent IR node.
        """
        return self._parent

    @property
    def block(self) -> Block:
        """
        Returns:
            Body of the try/catch clause.
        """
        return self._block

    @property
    def error_name(self) -> str:
        """
        !!! example
            For the following snippet:
            ```solidity
            try this.f() returns (uint256) {
                // ...
            } catch Error(string memory reason) {
                // ...
            } catch Panic(uint errorCode) {
                // ...
            } catch (bytes memory lowLevelData) {
                // ...
            }
            ```

            - is empty for the first (try) clause,
            - is `Error` for the second (catch) clause,
            - is `Panic` for the third (catch) clause,
            - is empty for the fourth (catch) clause.

        Returns:
            Error name of the try/catch clause.
        """
        return self._error_name

    @property
    def parameters(self) -> Optional[ParameterList]:
        """
        Can be `None` if the try clause does not have return parameters or if the catch clause does not accept parameters.
        !!! example
            Both clauses in the following example do not have parameters:
            ```solidity
            try this.f() {
                // ...
            } catch {
                // ...
            }
            ```

        !!! example
            `:::solidity (uint x)`, `:::solidity (string memory reason)`, `:::solidity (uint errorCode)` and `:::solidity (bytes memory lowLevelData)` are the parameters of the try/catch clauses in the following example:
            ```solidity
            try this.f() returns (uint x) {
                // ...
            } catch Error(string memory reason) {
                // ...
            } catch Panic(uint errorCode) {
                // ...
            } catch (bytes memory lowLevelData) {
                // ...
            }
            ```

        Returns:
            Return parameters in the case of a try clause, or error parameters in the case of a catch clause.
        """
        return self._parameters

    @property
    @lru_cache(maxsize=2048)
    def modifies_state(
        self,
    ) -> Set[Tuple[Union[ExpressionAbc, StatementAbc, YulAbc], ModifiesStateFlag]]:
        return self.block.modifies_state

block: Block property

Returns:

Type	Description
Block	Body of the try/catch clause.

error_name: str property

Example

For the following snippet:

try this.f() returns (uint256) {
    // ...
} catch Error(string memory reason) {
    // ...
} catch Panic(uint errorCode) {
    // ...
} catch (bytes memory lowLevelData) {
    // ...
}

• is empty for the first (try) clause,
• is Error for the second (catch) clause,
• is Panic for the third (catch) clause,
• is empty for the fourth (catch) clause.

Returns:

Type	Description
str	Error name of the try/catch clause.

parameters: Optional[ParameterList] property

Can be None if the try clause does not have return parameters or if the catch clause does not accept parameters.

Example

Both clauses in the following example do not have parameters:

try this.f() {
    // ...
} catch {
    // ...
}

Example

(uint x), (string memory reason), (uint errorCode) and (bytes memory lowLevelData) are the parameters of the try/catch clauses in the following example:

try this.f() returns (uint x) {
    // ...
} catch Error(string memory reason) {
    // ...
} catch Panic(uint errorCode) {
    // ...
} catch (bytes memory lowLevelData) {
    // ...
}

Returns:

Type	Description
Optional[ParameterList]	Return parameters in the case of a try clause, or error parameters in the case of a catch clause.

parent: TryStatement property

Returns:

Type	Description
TryStatement	Parent IR node.