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Re: A Macro for Steppers
- To: <xanadu!tribble>, <xanadu!xanadu!mark>
- Subject: Re: A Macro for Steppers
- From: Michael McClary <xanadu!michael>
- Date: Mon, 11 Dec 89 18:11:29 PST
- Cc: <eric@son-of-blob>, <xtech@son-of-blob>
> From xanadu!tribble Mon Dec 11 13:48:55 1989
> A problem arises when the action in the Stepper loop involves a return
> from the embodying function. The execution scopes of X++ and Smalltalk
> differ somewhat here: A return in the X++ macro will return from the
> function that uses the macro, whereas a return in the block in Smalltalk
> would just return from the block, but not the calling method. ...
> I believe that a return from the block in Smalltalk also returns from
> the invoking method, so the two languages agree here. I'm also not
> sure, Dean??
> Yes. It's quite annoying that there is no convenient way to
> explicitly return out of a block except by falling off the end.
> Smalltalk has the same return semantics as a return expression in X++.
How hard would it be to ADD analogs of break; and/or continue; to the
smalltalk we're using? Is this an hour's's hack, or a major project?
(If it's being a prototyping tool for C++, it really ought to be able to
generate the same flow constructs.)