[Ecls-list] Macros impossible in compiled function

[Peter Enerccio]

Ah, right, I know why it is impossible. At the point of compilation of the
lambda macro doesnt exists yet. Duh. Sorry about that.


2012/12/11 Peter Enerccio <enerccio at gmail.com>

> Ah, thank you. I guess that was the problem, I didn't think about the
> local definition, since technically, you can define function and use it
> right away in the same local code. I will have to think how to remedy it, I
> suppose.
>
> The reason why there is in-package is strange, because I don't know what
> does in-package do in ecl, but if the in-package is not there, the results
> are undefined (for instance when there is unbound symbol, it will not
> report the error as condition, for instance) thus I left it there, even
> though it has zero technical meaning, because there is no reading involved
> at that point.
>
> As for the reason why, it's because the whole code there is compiled into
> function which is then called at later time in different thread.
> Results are like this then:
> http://img15.hostingpics.net/pics/864433capture1355165935.png
>
>
> 2012/12/11 Juan Jose Garcia-Ripoll <juanjose.garciaripoll at gmail.com>
>
>> On Tue, Dec 11, 2012 at 12:58 AM, Peter Enerccio <enerccio at gmail.com>wrote:
>>
>>> Macrolet will make possible to do local macros, which are fine, but this
>>> is not what I meant.
>>> What I wanted is to define macros "safely", because the code is
>>> evaluated in different thread with safe symbols, thus it is first saved
>>> as lazy function.
>>>
>>
>> You can define a global macro. You cannot apply it in the same form which
>> defines it because it is a local form. Note that this has nothing to do
>> with ECL, but with your understanding of Common Lisp.
>>
>>
>> (LAMBDA ()
>>   ;; Mistake 1. Assume that the forms below change the package
>>   ;; and that the IN-PACKAGE form will affect the DEFMACRO
>>   (LET ((CORE::P *PACKAGE*) (CORE:THIS #<a GAME:CUBE>))
>>     ;; This IN-PACKAGE does nothing because none of what follows
>>     ;; uses the value of *package*
>>
>>     (IN-PACKAGE ANCA)
>>     (HANDLER-CASE
>>      (UNWIND-PROTECT
>>          (PROGN
>>           (PROGN
>>             (DEFMACRO ANCA::RUNNABLE (&BODY ANCA::BODY)
>>              (SI:QUASIQUOTE (LAMBDA () (SI:UNQUOTE-SPLICE ANCA::BODY))))
>>          ;; MISTAKE 2: Assume that RUNNABLE can be used right after
>> DEFMACRO
>>          ;; This is not possible because this is in a LAMBDA
>>
>>            ((ANCA::RUNNABLE (PRINT "Ahoj")))))
>>        (SETF *PACKAGE* CORE::P))
>>      (T (CORE::X)
>>       (FUNCALL
>>        #<bytecompiled-closure #<bytecompiled-function 00000000032387d0>>
>>        #<a GAME:CUBE>
>>        CORE::X)))
>>     T))
>>
>> If you want to define a macro, evaluate a form that defines it. This
>> changes the global status of your Lisp and the macro will be available to
>> further forms which are evaluated later.
>>
>> (defun define-my-macro ()
>>    (defmacro foo (a) `(print ,a)))
>>
>> This is a perfectly fine code. If you run
>>
>> (define-my-macro)
>>
>> it will define the macro. And now you can type
>>
>> (foo 2)
>>
>> and this will be translated to (print 2). That's all.
>>
>> But really, I do not understand what you want to achieve with the code
>> above and I think you need to learn more Common Lisp before just trying to
>> run any code.
>>
>> Juanjo
>>
>> --
>> Instituto de Física Fundamental, CSIC
>> c/ Serrano, 113b, Madrid 28006 (Spain)
>> http://juanjose.garciaripoll.googlepages.com
>>
>
>
>
> --
> Bc. Peter Vaňušanik
> http://www.bishojo.tk
>
>


-- 
Bc. Peter Vaňušanik
http://www.bishojo.tk
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