Re: [Chicken-hackers] [PATCH] [5] Aggressively reject definitions in expression contexts (#1309)

[Peter Bex]

Now with attachments...

On Sat, Feb 25, 2017 at 06:13:48PM +0100, Peter Bex wrote:
> On Sat, Feb 11, 2017 at 03:37:35PM +0100, Peter Bex wrote:
> > On Mon, Dec 12, 2016 at 09:38:17AM +0100, Peter Bex wrote:
> > > I'll ponder this some more as well.
> > 
> > Here's a very patch which _doesn't_ require macros to know they're
> > being evaluated at toplevel or not.
> 
> Here's an update with this patch plus two related patches which fix
> an occurrance of a "define" in an invalid context in CHICKEN core
> which you'll see when you try to recompile CHICKEN with itself after
> having applied the first patch.
> 
> This originally worked because the define would be a global one, which
> is quite broken!  I think erroring out early is a nice benefit.
> Finally, the third patch here fixes a bug that we inadvertently
> introduced when we made chicken.expand into a module: because these
> internal definitions like chicken.expand#define-definition weren't
> exported, and they're not set! inside the module, the compiler assumed
> it would never be set, so it would inline the values, which means the
> definitions would always be compared with #<unspecified>.
> 
> However, I figured out that the real cause of #1309 is much, much deeper
> and has to do with a nasty bug in ##sys#canonicalize-body: it invokes
> "fini" as soon as it sees a non-pair.  However, fini doesn't handle
> expansions the same way as the body.  For example:
> 
>   (let () 1 (begin (define blabla 3)) blabla)
> 
> This will define blabla globally (or trigger an error in CHICKEN 5 with
> the patch), because the "1" stops the begin from being expanded properly.
> I fear that this requires a pretty invasive rewrite of
> ##sys#canonicalize-body.  I'll get back to y'all on that.
> 
> Cheers,
> Peter

0001-Reject-toplevel-definitions-in-non-toplevel-contexts.patch
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0002-Fix-invalid-definition-caught-by-previous-commit.patch
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0003-Export-internal-define-like-definitions-from-chicken.patch
Description: Text Data

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