Hi Jens - <br><br>thanks for the quick reply. After some more
researching plus looking at your code I realized where my mistakes are
- I thought symbols in a syntax expands out to itself, but apparently
this is not the case (hence my problem has nothing to do with
module/macros). Instead, I need to use datum->syntax-object to make
sure that timeout in syntax equals timeout in symbol (BTW - thanks for
your example showing below using stx as the context syntax... I was
scratching my head trying to figure out where I can provide a context).
<br><br>However, looking at your code there are some concepts that I don't understand: <br><ul><li>your
code provides syntax name for time-out and main rather than timeout,
start, initial-request, and interface-version - why this also works
without having to convert them to syntax-object? <br></li><li>how does the nested define-syntax work both in terms of expansion and scoping? </li><li>Aesthetics
and styles aside - is there a reason for nested define-syntax? (It
looks cool to learn, but I came from the C world where definitions
belong on top level, so want to know why and how I can think in this
fashion) <br></li></ul>Below is what I have right now that works... yours seem shorter ;) <span class="q"><br><br>(module syntax-util mzscheme <br> (provide (all-defined)) <br><br></span> (define-syntax time-out <span class="q">
<br> (lambda (stx) <br> (syntax-case stx ()
<br></span> ((_ t) <br> (with-syntax ((timeout (datum->syntax-object stx 'timeout))) <br> #'(define timeout t))))))<br> <br> (define-syntax main <span class="q"><br> (lambda (stx)
<br> (syntax-case stx ()
<br> ((_ body ...) <br></span> (with-syntax ((start (datum->syntax-object stx 'start))<br> (initial-request (datum->syntax-object stx 'intial-request))) <br> #'(define (start initial-request)
<br> body ...))))))<span class="q"><br> <br> (define-syntax servlet <br> (lambda (stx) <br> (syntax-case stx () <br> ((_ body ...) <br></span> (with-syntax ((interface-version (datum->syntax-object stx 'interface-version)))
<br> #'(begin <span class="q"><br> body ...<br> (define interface-version 'v1)<br> (provide (all-defined))))))))) <br><br></span><span class="q">(module webtest1 mzscheme
<br> (require syntax-util) <br>
(servlet <br> (time-out +inf.0)<br> (main '(p "hello world")))) <br><br>(require webtest1) <br><br></span>timeout ; => +inf.0<br>interface-version ; => 'v1 <br>(start null) ; => '(p "hello world")
<br><br>Thanks,<br>yinso <div><span class="q" id="q_11201dbfb82e1b00_12"><br><br><br><div><span class="gmail_quote">On 4/17/07, <b class="gmail_sendername">Jens Axel Søgaard</b> <<a href="mailto:jensaxel@soegaard.net" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
jensaxel@soegaard.net</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi Yin-So,<br><br>Here is one way to do it:<br><br>(module syntax-util mzscheme<br> (provide (all-defined))<br><br> (define-syntax servlet<br> (lambda (stx)<br> (syntax-case stx ()<br> ((_ body ...)
<br>
(with-syntax ([time-out (datum->syntax-object stx 'time-out)]<br> [main (datum->syntax-object stx 'main)])<br> #`(begin<br> (define-syntax (time-out stx)
<br> (syntax-case stx ()<br> ((_ value)<br> #'(begin<br> (define timeout value)<br> (provide timeout)))))<br> (define-syntax (main stx)
<br> (syntax-case stx ()<br> [(_ body1 (... ...))<br> #'(define start<br> (lambda (initial-request)<br> body1 (... ...)))]))
<br> body ...<br> (define interface-version 'v1)<br> (provide (all-defined))<br> ))))))<br> )<br><br> (require syntax-util)<br><br> (module webtest1 mzscheme
<br> (require syntax-util)<br> (servlet<br> (time-out +inf.0)<br> (main `(p "hello world"))<br> ))<br><br> (require webtest1)<br><br> timeout<br><br><br>I moved the definitions of time-out and main into the expansion of
<br>servlet, since they need to be in the scope of the forms of body ... .<br>Note that when expanding into ... one needs to write (... ...).<br><br>Also, to provide a name such as timeout, the provide form must have<br>
the same syntactic context as the definition. The easiest way to ensure
<br>this is, to put a provide-clause next to the definition.<br><br>--<br>Jens Axel Søgaard<br><br><br><br>--<br>Jens Axel Søgaard<br><br></blockquote></div><br><br clear="all"><br></span></div><div><span class="q" id="q_11201dbfb82e1b00_13">
-- <br><a href="http://www.yinsochen.com/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
http://www.yinsochen.com</a><br>...continuous learning...
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