[racket-dev] syntax-property guards? (was: Re: The Stepper strikes again)

From: Eli Barzilay (eli at barzilay.org)
Date: Tue Aug 16 17:10:58 EDT 2011

Three minutes ago, John Clements wrote:
> On Aug 16, 2011, at 4:41 PM, Eli Barzilay wrote:
> > Earlier today, Stephen Chang wrote:
> >> 
> >> It seems like most people agree that it's ok to add stepper syntax
> >> properties to lazy racket.
> > 
> > I agree with that in general while development is ongoing, but
> > eventually it should be disconnected too.
> I don't see how to do this. To make sure we're on the same page, I'm
> suggesting that it's very difficult to make statements about places
> in the expanded code without adding annotations to the text of the
> expansions themselves.

A possible conclusion would be that it's useful to know these kind of
things about an expanded piece of syntax, and therefore more macros
should do that -- but that's unrelated from the stepper, which is
merely the motivation for requiring such functionality.  Just like
continuation marks being useful for the stepper, becoming part of the
core language, and then getting used for much more.

          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                    http://barzilay.org/                   Maze is Life!

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