From gwking at metabang.com  Wed Nov 26 01:13:38 2008
From: gwking at metabang.com (Gary King)
Date: Tue, 25 Nov 2008 20:13:38 -0500
Subject: [Metatilities-devel] One more bug
In-Reply-To: <4be8713d0811251651i4571fe52h751868899cf918@mail.gmail.com>
References: <4be8713d0811251651i4571fe52h751868899cf918@mail.gmail.com>
Message-ID: <8C87BD2A-4364-40DD-95F7-34733DB98B50@metabang.com>

Hi Gustavo

Thanks for the detailed report. I haven't looked at (or even used!)  
this code for a _long_ time so it wouldn't surprise me if its broken.  
I'll see what I can do over the Thanksgiving break.

regards,

On Nov 25, 2008, at 7:51 PM, Gustavo wrote:

> The compiler macros for functions disjoin and conjoin are broken.  
> For debugging purposes, I copied the code to a macro to see what was  
> happening.
>
> cl-user> (in-package :metatilities)
> #<package "METABANG.UTILITIES">
> utilities> (defmacro disjoin* (&whole form &rest fns)
>   (cond ((every #'(lambda (x) (or (symbolp x) (function-expression-p  
> x))) fns)
>          (with-unique-names (args)
>            `#'(lambda (,args)
>                 (or ,@(mapcar #'(lambda (x)
>                                   `(apply ,(extract-head-form x)
>                                           ,args))
>                               fns)))))
>         (t form)))
> disjoin*
> utilities> (macroexpand-1 '(disjoin* #'macro-char-p #'whitespace-p))
> #'(lambda (#:|args/1399|)
>     (or (apply macro-char-p #:|args/1399|) (apply whitespace-p #:| 
> args/1399|)))
> t
>
> I realized this bug trying to compile a function - sbcl complained  
> about the variables macro-char-p and whitespace-p not to be defined.  
> That makes me wonder: what is "extract-head-form" doing? It should  
> be usefull only if you did something like:
>
> (define-compiler-macro disjoin (fn &rest fns)
>   ...
>     `(,(extract-head-form x) , at args)
>   ...
> )
>
> I.e., eliminating the funcalls (I saw that somewhere on cliki.net  
> some time ago).And, by the way, I guess that, the way the function  
> disjoin is being defined, I guess there is no way to do this (the  
> argument list is only known in execution time).

--
Gary Warren King, metabang.com
Cell: (413) 559 8738
Fax: (206) 338-4052
gwkkwg on Skype * garethsan on AIM




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