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[bug #31472] Probable psyntax bug with multiple defininitions in the mac

From: Göran Weinholt
Subject: [bug #31472] Probable psyntax bug with multiple defininitions in the macro expansion
Date: Sat, 21 May 2011 13:46:44 +0000
User-agent: Mozilla/5.0

Follow-up Comment #2, bug #31472 (project guile):

Hello guilers,

I want to note some problems that I suspect are caused by this bug. In
this example it looks like (define-foo foo1) and (define-foo foo2) use
the same identifier for `t' (the latter definition overrides the

GNU Guile
Copyright (C) 1995-2011 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> (library (temporaries-bug)
                       (export foo1 foo2)
                       (import (rnrs))

                       (define-syntax define-foo
                         (lambda (x)
                           (syntax-case x ()
                             ((_ name)
                              (identifier? #'name)
                                  (define t '(foo name))
                                  (define (name) t))))))

                       (define-foo foo1)
                       (define-foo foo2))
scheme@(temporaries-bug)> ,m (guile-user)
scheme@(guile-user)> (import (temporaries-bug))
scheme@(guile-user)> (foo1)
$1 = (foo foo2)
scheme@(guile-user)> (foo2)
$2 = (foo foo2)

One can workaround this issue by using generate-temporaries. But that
doesn't work when (name) is syntax. Here I expect the library to
export syntax that can be used as (foo3), which would evaluate to the
list (foo foo3):

scheme@(guile-user)> (library (temporaries2-bug)
                       (export foo3 foo4)
                       (import (rnrs))

                       (define-syntax define-foo
                         (lambda (x)
                           (syntax-case x ()
                             ((_ name)
                              (identifier? #'name)
                              (with-syntax (((t) (generate-temporaries
                                    (define t '(foo name))
                                    (define-syntax name
                                      (lambda (x)
                                        (syntax-case x ()
                                          ((_) #'t))))))))))

                       (define-foo foo3)
                       (define-foo foo4))
scheme@(temporaries2-bug)> ,m (guile-user)
scheme@(guile-user)> (import (temporaries2-bug))
scheme@(guile-user)> (foo3)
;;; <stdin>:7:0: warning: possibly unbound variable `#{ g238}#'
<unnamed port>:6:0: In procedure #<procedure 1e50a00 at <current input>:7:0
<unnamed port>:6:0: In procedure module-lookup: Unbound variable: #{ g238}#

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> 


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