This seems to work (blind hack), I really don't know what syntax-local-make-definition-context and syntax-local-bind-syntaxes does <div>I can only assume that they introduce some kind of bindings in particular context.</div>
<div><br><div><br></div><div><div>(define-syntax (depgraph stx)</div><div> (syntax-parse stx</div><div> [(_ ((id:id expr:expr ...) ...))</div><div> </div><div> (define id-lst (syntax->list #'(id ...)))</div>
<div> (define ctx (syntax-local-make-definition-context))</div><div> (syntax-local-bind-syntaxes id-lst #f ctx)</div><div> (with-syntax ([p #'((lambda () expr ...) ...)])</div><div> (define p-lst (syntax->list #'p))</div>
<div> (define vars</div><div> (map (lambda (e) </div><div> (free-vars</div><div> (local-expand e 'expression '() ctx))) p-lst))</div><div> (with-syntax ([((f ...) ...) vars])</div>
<div> #''((id (f ...)) ...)))]))</div><div> </div><div> </div><div>(define simple-arith</div><div> (depgraph</div><div> ((a #f)</div><div> (b (* 3 a))</div><div> (c (+ 5 a b))</div><div> (d (let ((a 9)) (- c a))) )))</div>
<div><br></div><div>simple-arith </div><div>;((a ()) (b (a)) (c (b a)) (d (c)))</div><div><br></div><br><br><div class="gmail_quote">On Wed, Jan 18, 2012 at 1:46 PM, Marijn <span dir="ltr"><<a href="mailto:hkBst@gentoo.org">hkBst@gentoo.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">-----BEGIN PGP SIGNED MESSAGE-----<br>
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</div><div class="im">On 17-01-12 16:14, Sam Tobin-Hochstadt wrote:<br>
> On Tue, Jan 17, 2012 at 4:06 AM, Marijn <<a href="mailto:hkBst@gentoo.org">hkBst@gentoo.org</a>> wrote:<br>
>> On 16-01-12 15:28, Sam Tobin-Hochstadt wrote:<br>
>>> On Mon, Jan 16, 2012 at 7:57 AM, Marijn <<a href="mailto:hkBst@gentoo.org">hkBst@gentoo.org</a>><br>
>>> wrote:<br>
>>>><br>
>>>> ((_ ((id rule) ...)) (with-syntax (((dep ...) (free-vars<br>
>>>> (expand #'(rule ...)))))<br>
>>><br>
>>> You need to use `local-expand', not `expand', here. Probably<br>
>>> like this:<br>
>>><br>
>>> (local-expand #'(rule ...) 'expression '())<br>
>>><br>
>><br>
>> If I use that instead I still get the same error. Perhaps it<br>
>> needs to be something like:<br>
>><br>
>> (local-expand #'(rule ...) 'expression '(id ...))<br>
>><br>
>> but '(id ...) is not in the right form...<br>
><br>
> Ah, I see the problem. You're trying to expand expressions with<br>
> unbound variables, and they give an expansion error as they<br>
> should. You might be able to use the stop list to make this work,<br>
> but the right solution is to bind the variables.<br>
<br>
</div>I don't understand how or where I should bind these identifiers that<br>
I'm trying to detect are free. A working example of how to use<br>
free-vars would really help.<br>
<div class="im"><br>
Marijn<br>
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