bug#12929: case-lambda*

bug#12929: case-lambda*

[Daniel Llorens]

See the thread here 

http://lists.gnu.org/archive/html/guile-user/2012-11/msg00032.html

In Guile 2.0.6

(define f (case-lambda*
             ((x #:optional y) 1)
	     ((x #:key y)      2)
	     ((x y #:key z)    3)))

(f 1 2 #:z 3) -> Odd length of keyword argument list

Also

(define g (case-lambda*
                      ((a #:key x) 1)
                      ((a b c #:key x) 3)))

(g 1 2 3) - > Invalid keyword

This behavior doesn't seem useful and doesn't follow from the doc on case-lambda*, which is rather vague and lacks examples.

The case-lambda* test in tree-il.test also fails on the REPL

(let ((f (case-lambda*
          ((x #:optional y) 1)
          ((x #:key y)      2)
          ((x y #:key z)    3))))
  (list (f 1)
        (f 1 2)
        (f #:y 2)
        (f 1 2 #:z 3)))

-> Odd length of keyword argument list

Thanks,

	Daniel

bug#12929: case-lambda*

[Ludovic Courtès]

Hi,

Indeed, there’s something wrong.  The “Odd length” error comes from the
‘bind-kwargs’ corresponding to the first case of the ‘case-lambda*’:

--8<---------------cut here---------------start------------->8---
scheme@(guile-user)> (case-lambda*
	     ((x #:key y)      2)
	     ((x y #:key z)    3))
$63 = #<procedure 22a0d40 at <current input>:4761:0 (x #:key y) | (x y #:key z)>
scheme@(guile-user)> ($63 1 2  #:z 3)
<unnamed port>:4761:0: In procedure #<procedure 22a0d40 at <current input>:4761:0 (x #:key y) | (x y #:key z)>:
<unnamed port>:4761:0: In procedure #<procedure 22a0d40 at <current input>:4761:0 (x #:key y) | (x y #:key z)>: Odd length of keyword argument list

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> ,proc
$64 = #<procedure 22a0d40 at <current input>:4761:0 (x #:key y) | (x y #:key z)>
scheme@(guile-user) [1]> ,x $64
Disassembly of #<procedure 22a0d40 at <current input>:4761:0 (x #:key y) | (x y #:key z)>:

   0    (br-if-nargs-lt 0 1 :L49541)    ;; -> 34
   6    (bind-optionals/shuffle 0 1 0 1 0 2)
  13    (bind-kwargs 0 1 0 2 0)         
  19    (reserve-locals 0 2)            
  22    (local-bound? 1)                
  24    (br-if :L49542)                 ;; -> 31
  28    (make-false)                    
  29    (local-set 1)                   ;; `y'
  31    (make-int8 2)                   ;; 2
  33    (return)                        
  34    (assert-nargs-ge 0 2)           
  37    (bind-optionals/shuffle 0 2 0 2 0 3)
  44    (bind-kwargs 0 2 0 3 0)         
  50    (reserve-locals 0 3)            
  53    (local-bound? 2)                
  55    (br-if :L49543)                 ;; -> 62
  59    (make-false)                    
  60    (local-set 2)                   ;; `z'
  62    (make-int8 3)                   ;; 3
  64    (return)                        

scheme@(guile-user) [1]> ,regs
  Registers:
  $65 = ip = 19
  $66 = sp = #x2dacd58
  $67 = fp = #x2dacd38
--8<---------------cut here---------------end--------------->8---

Seems to me that for this to work, we’d need a variant of ‘bind-kwargs’,
say ‘br-if-kwargs-match’, that allows a jump to the next case upon
mismatch.

At least, I can’t think of any other way to generate a prelude that
would work (search for <glil-kw-prelude> in compile-assembly.scm.)

Thoughts?

Thanks,
Ludo’.

bug#12929: case-lambda*

[Andy Wingo]

On Mon 19 Nov 2012 11:38, Daniel Llorens <dll@jast.ch> writes:

> http://lists.gnu.org/archive/html/guile-user/2012-11/msg00032.html

Fixed, with notes in that thread.  Thanks again for the report!

Andy
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