GNU bug report logs - #14449
Guile 2.1 and macro nesting

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Sanel Zukan <sanelz <at> gmail.com>
To: bug-guile <at> gnu.org
Subject: Guile 2.1 and macro nesting
Date: Thu, 23 May 2013 15:50:32 +0200

Hi,

Looks like macro nesting (using define-macro) inside guile 2.x is no
longer possible. Here is example:

-----------------------------------------
scheme@(guile-user)>
(define-macro (def-caller abbrev proc)
    `(define-macro (,abbrev var expr)
       `(,',proc
         (lambda (,var) ,expr))))

scheme@(guile-user)> (def-caller katch call/cc)
scheme@(guile-user)> (macroexpand '(katch 3 (+ 1 1)))
ice-9/psyntax.scm:2146:53: In procedure #<procedure 282adc0 (args e1
e2)>:
ice-9/psyntax.scm:2146:53: Syntax error:
unknown location: lambda: invalid argument list in subform (3) of (3)

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to
continue.
-----------------------------------------

However, doing the same in guile 1.x and/or any other Scheme
implementation where define-macro is native, it works without
problems.

Best,
Sanel

Message #10 received at 14449-done <at> debbugs.gnu.org (full text, mbox):

From: Ian Price <ianprice90 <at> googlemail.com>
To: Sanel Zukan <sanelz <at> gmail.com>
Cc: 14449-done <at> debbugs.gnu.org
Subject: Re: bug#14449: Guile 2.1 and macro nesting
Date: Thu, 03 Oct 2013 10:11:30 +0100

tags 14449 notabug
thanks

Sanel Zukan <sanelz <at> gmail.com> writes:

> scheme@(guile-user)>
> (define-macro (def-caller abbrev proc)
>     `(define-macro (,abbrev var expr)
>        `(,',proc
>          (lambda (,var) ,expr))))
>
> scheme@(guile-user)> (def-caller katch call/cc)
> scheme@(guile-user)> (macroexpand '(katch 3 (+ 1 1)))
> ice-9/psyntax.scm:2146:53: In procedure #<procedure 282adc0 (args e1
> e2)>:
> ice-9/psyntax.scm:2146:53: Syntax error:
> unknown location: lambda: invalid argument list in subform (3) of (3)
>
> Entering a new prompt.  Type `,bt' for a backtrace or `,q' to
> continue.

Sorry it's taken so long. This is not a bug. You are using a number as
a variable in a lambda list, nothing to do with defmacro.

scheme@(guile-user)> (macroexpand '(lambda (3) (+ x 1)))
ice-9/psyntax.scm:2156:53: In procedure #<procedure 8e000a0 (args e1 e2)>:
ice-9/psyntax.scm:2156:53: Syntax error:
unknown location: lambda: invalid argument list in subform (3) of (3)

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.


If you use a variable name, it works correctly.


scheme@(guile-user)> (define-macro (def-caller abbrev proc)
    `(define-macro (,abbrev var expr)
       `(,',proc
         (lambda (,var) ,expr))))
scheme@(guile-user)> (def-caller katch call/cc)
scheme@(guile-user)> (macroexpand '(katch x (+ 1 1)))
$2 = #<tree-il (call (toplevel call/cc) (lambda () (lambda-case (((x) #f
    #f #f () (x-478)) (call (toplevel +) (const 1) (const 1))))))>
scheme@(guile-user)> ,expand (katch a (+ 1 1))
$3 = (call/cc (lambda (a) (+ 1 1)))
scheme@(guile-user)> (katch a (+ 1 (a 3)))
$4 = 3


I'm closing this one.

-- 
Ian Price -- shift-reset.com

"Programming is like pinball. The reward for doing it well is
the opportunity to do it again" - from "The Wizardy Compiled"

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