Errors and Exceptions in Newspeak

[Rouan van Dalen]

Hi everyone,

Why do we have Error and Exception in Newspeak?

And when do I use which?

Currently I am using:

    Error signal: 'some error message'

for signalling general exceptions

If I would like my to create my own specialised exception class, do I inherit from Error or Exception?

Regards

--Rouan

[Frank Shearar]

Exception is the base class for all non-local signalling. Its two main
subclasses are Notification and Error.

If something bad goes wrong, you want to signal Error.

Some kinds of Exceptions are resumable: look at implementors of #isResumable.

frank

> Regards
> --Rouan

[Eliot Miranda]

On Fri, Apr 19, 2013 at 6:37 AM, Rouan van Dalen <r...@sftreal.co.za> wrote:

Hi everyone,

Why do we have Error and Exception in Newspeak?

And when do I use which?

Currently I am using:

    Error signal: 'some error message'

for signalling general exceptions

You might want to implement error: at the top=-level of your module:

error: str = (Error signal: str)

It's a nice short-hand; I miss it not being in Newspeak's Object.  Interesting tension between having useful facilities in Object with inevitable dependencies, vs defining everything oneself, defining the dependencies explicitly but reinventing the wheel and/or writing much more verbose code.

If I would like my to create my own specialised exception class, do I inherit from Error or Exception?

From Error, or one of its subclasses.

 

Regards

--Rouan

--
best,

Eliot

[Rouan van Dalen]

Thanks Frank & Eliot,

I have a better idea of where to go from here with exceptions.

I do not create the error: shorthand.

What I implement at the top module is just a binding to the Error class:

    private Error = platform exceptions Error.

and then write code like this:

    index > list size

        ifTrue: [ Error signal: 'index too high' ].

Regards

--Rouan