[ clisp-Bugs-1731462 ] bogus expansion when using EXT:LETF with more than one place

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Bugs item #1731462, was opened at 2007-06-05 16:59
Message generated for change (Comment added) made by hoehle
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Category: clisp
Group: lisp error
>Status: Closed
>Resolution: Fixed
Priority: 5
Private: No
Submitted By: Jörg Höhle (hoehle)
>Assigned to: Jörg Höhle (hoehle)
Summary: bogus expansion when using EXT:LETF with more than one place

Initial Comment:
Hi,

Looking at CLISP macroexpansions after my (gensym "NAME-") patches made me uncover 2 bugs. Here is one.

(ext:letf (((car x) 1)) (princ x))             ; ok
(ext:letf (((car x) 1) ((cdr x) 2)) (princ x)) ; bogus
(LETF* ((#:TEMP-3605 X) (#:NEW-3604 (CAR #:TEMP-3605)) (#:G3606 1))
 (UNWIND-PROTECT
  (PROGN (SYSTEM::%RPLACA #:TEMP-3605 #:G3606)
   (SYSTEM::%RPLACD #:TEMP-3602 #:G3603) (PRINC X))
  (SYSTEM::%RPLACA #:TEMP-3605 #:NEW-3604)
  (SYSTEM::%RPLACD #:TEMP-3602 #:NEW-3601)))

ext:letf* seems not affected.

(ext:letf (((car x) 1) ((ldb (byte 6 8) (aref y 2)) 3)) (princ x))
"3" is not found in expansion
#:6281 (new value) is never bound
(LETF* ((#:TEMP-6283 X) (#:NEW-6282 (CAR #:TEMP-6283)) (#:G6284 1))
 (UNWIND-PROTECT
  (PROGN (SYSTEM::%RPLACA #:TEMP-6283 #:G6284)
   (LET ((#:G6278 (DPB #:G6281 #:BYTESPEC-6279 (AREF #:G6276 #:G6277))))
    (SYSTEM::STORE #:G6276 #:G6277 #:G6278) #:G6281)
   (PRINC X))
  (SYSTEM::%RPLACA #:TEMP-6283 #:NEW-6282)
  (LET ((#:G6278 (DPB #:NEW-6280 #:BYTESPEC-6279 (AREF #:G6276 #:G6277))))
   (SYSTEM::STORE #:G6276 #:G6277 #:G6278) #:NEW-6280)))
A single (ext:letf (#) ...) is not affected
(ext:letf (((ldb (byte 6 8) (aref y 2)) 3)) (princ x))
- but possibly not optimal (or correct?)

Same for
(setf (char-bit (aref y 2) :control) t) ; ok
(ext:letf (((char-bit (aref y 2) :control) t)) (princ x)) ; weird?
 -- why is aref called 3 times? 1 could be enough.
(LETF*
 ((#:G6325 Y) (#:G6326 2) (#:G6328 :CONTROL)
  (#:G6329 (CHAR-BIT (AREF #:G6325 #:G6326) #:G6328)) (#:G6330 T))
 (UNWIND-PROTECT
  (PROGN
   (LET ((#:G6327 (SET-CHAR-BIT (AREF #:G6325 #:G6326) #:G6328 #:G6330)))
    (SYSTEM::STORE #:G6325 #:G6326 #:G6327) #:G6330)
   (PRINC X))
  (LET ((#:G6327 (SET-CHAR-BIT (AREF #:G6325 #:G6326) #:G6328 #:G6329)))
   (SYSTEM::STORE #:G6325 #:G6326 #:G6327) #:G6329)))

There's not a single test for EXT:EXTF in the whole testsuite!  What would be a good file to add them (create a new file?)


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Comment By: Jörg Höhle (hoehle)
Date: 2007-06-06 16:23

Message:
Logged In: YES 
user_id=377168
Originator: YES

thank you for your bug report.
the bug has been fixed in the CVS tree.
you can either wait for the next release (recommended)
or check out the current CVS tree (see http://clisp.cons.org)
and build CLISP from the sources (be advised that between
releases the CVS tree is very unstable and may not even build
on your platform).

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Comment By: Sam Steingold (sds)
Date: 2007-06-05 17:02

Message:
Logged In: YES 
user_id=5735
Originator: NO

new file is best because this is a clisp extension

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