Try catch clause

woke.ast.ir.meta.try_catch_clause module

TryCatchClause class

Bases: SolidityAbc

Example

• returns(uint x) {},
• catch Error(string memory reason) {},
• catch Panic(uint errorCode) {},
• catch (bytes memory lowLevelData) {} are all try/catch clauses in the following example:

  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 woke/ast/ir/meta/try_catch_clause.py

class TryCatchClause(SolidityAbc):
    """
    !!! example
        - `:::solidity returns(uint x) {}`,
        - `:::solidity catch Error(string memory reason) {}`,
        - `:::solidity catch Panic(uint errorCode) {}`,
        - `:::solidity catch (bytes memory lowLevelData) {}` are all try/catch clauses in the following example:
        ```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) {
                // ...
            }
            ```

            - the `error_name` of the first (try) clause is empty,
            - the `error_name` of the second (catch) clause is `Error`,
            - the `error_name` of the third (catch) clause is `Panic`,
            - the `error_name` of the fourth (catch) clause is empty.
        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[IrAbc, 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) {
    // ...
}

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

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.