Trying to upgrade to the latest PS, I have a problem with this CASE fix:<br>it rejects symbol macros that expand to numbers. It's quite handy to<br>use symbol macros this way for compile-time constants, so I hope<br>the desired behavior can be restored.<br>
<br>Daniel<br><br><br><div class="gmail_quote">On Mon, Sep 3, 2012 at 7:22 PM, Vladimir Sedach <span dir="ltr"><<a href="mailto:vsedach@gmail.com" target="_blank">vsedach@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
This I would definitely call a bug. Since the position PS takes right<br>
now is that it doesn't have symbols as run-time objects, I made the<br>
decision to disallow them as keys in CASE clauses. Only keyword<br>
symbols (which are translated to strings), numbers and string literals<br>
are allowed.<br>
<br>
The behavior exhibited in your case is perfectly ok JavaScript though,<br>
so the SWITCH special form still supports having variables and others<br>
things as keys.<br>
<br>
I made a note in the reference manual (in the repo, I'll update the<br>
version on the PS website with the next release), and also fixed some<br>
other bugs I found in CASE and SWITCh statements.<br>
<br>
Thank you for bringing this issue up!<br>
<span class="HOEnZb"><font color="#888888"><br>
Vladimir<br>
</font></span><div class="HOEnZb"><div class="h5"><br>
On Mon, Sep 3, 2012 at 8:09 AM, Boris Smilga <<a href="mailto:boris.smilga@gmail.com">boris.smilga@gmail.com</a>> wrote:<br>
> Hello.<br>
><br>
> I've noticed that Parenscript has a different semantics from Lisp as<br>
> regards keys of CASE clauses. Lisp assumes an implicit QUOTE in this<br>
> context, so that a symbol used as CASE clause key matches a test-key<br>
> which is EQL to the symbol, as opposed to its value. Parenscript, on<br>
> the other hand, translates CASE forms to switch statements where<br>
> symbol keys are used as identifiers. E. g.<br>
><br>
> (let* ((foo 'bar) (bar 'foo) (x bar))<br>
> (case x ((foo) 1) ((bar) 2)))<br>
><br>
> translates to<br>
><br>
> (function () {<br>
> var foo = 'bar';<br>
> var bar = 'foo';<br>
> var x = bar;<br>
> switch (x) {<br>
> case foo:<br>
> return 1;<br>
> case bar:<br>
> return 2;<br>
> };<br>
> })();<br>
><br>
> Note that the former evaluates to 1, the latter to 2.<br>
><br>
> Now, is this a bug, or a feature? The section on CASE in the<br>
> Parenscript Manual is actually misleading, whatever the answer.<br>
><br>
> — B. Smilga.<br>
><br>
> _______________________________________________<br>
> parenscript-devel mailing list<br>
> <a href="mailto:parenscript-devel@common-lisp.net">parenscript-devel@common-lisp.net</a><br>
> <a href="http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel" target="_blank">http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel</a><br>
<br>
_______________________________________________<br>
parenscript-devel mailing list<br>
<a href="mailto:parenscript-devel@common-lisp.net">parenscript-devel@common-lisp.net</a><br>
<a href="http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel" target="_blank">http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel</a><br>
</div></div></blockquote></div><br>