Error Handling ​

Program Invocations ​

When a program returns a non-zero exit code, an exception is thrown. The exception can be handled as described in Catching.

Exceptions ​

Throwing ​

An exception can be thrown with the throw expression. The given value will be cast into an Error object, if it isn't one already.

throw "An error occurred"

throw "An error occurred"

Catching ​

An exception can be caught with the try/catch expression. When an exception is about the be caught, the first valid catch arm will be evaluated. The with <type> syntax is used to specify which kinds of values should be caught, based on the value inside the Error object.

The value of an Error object can be retrieved using the error::value function.

try {
    ls abc
    ...
} catch e with SomeStruct {
    println SomeStruct Error: ${error::value(e)}
} catch e {
    println Error: ${error::value(e)}
}

try {
    ls abc
    ...
} catch e with SomeStruct {
    println SomeStruct Error: ${error::value(e)}
} catch e {
    println Error: ${error::value(e)}
}