[cl-ppcre-devel] Warning from CMUCL 19a about CL-PPCRE 0.9.0 usage

[Edi Weitz]

On Fri, 19 Nov 2004 14:05:11 -0600, Kick Damien-DKICK1 <DKICK1 at motorola.com> wrote:

> I'm seeing some warnings from CMUCL that I don't understand.  Here
> is the warning the simplest code I've written at the moment that
> produces the warning:
>
> 	(defun flurp (line)
> 	  (let (delta)
> 	    (register-groups-bind (delta-str)
> 	        ('(:sequence (:register (:greedy-repetition 1 nil :digit-class)))
> 	          line)
> 	      (setq delta (parse-integer delta-str)))))
>
> and the warning:
>
> 	; In: DEFUN FLURP
>
> 	;   (REGISTER-GROUPS-BIND (DELTA-STR) ('# LINE) (SETQ DELTA #))
> 	; --> LET MULTIPLE-VALUE-BIND MULTIPLE-VALUE-CALL FUNCTION WHEN COND IF PROGN 
> 	; --> LET* LET 
> 	; ==>
> 	;   (IF #:START-INDEX5
> 	;       (FUNCALL #:SUBSTR-FN6 #:TARGET-STRING0 #:START-INDEX5 #)
> 	;       NIL)
> 	; Warning: This is not a (VALUES &OPTIONAL BASE-STRING &REST T):
> 	;   NIL
> 	; ; [Last message occurs 2 times]

CMUCL is clever, it knows that the first argument to PARSE-INTEGER
must be a string but in your function FLURP it is possible that
DELTA-STR is NIL (if there's no match). Thus the warning.

The form you're seeing in the warning is part of the macro expansion
of REGISTER-GROUPS-BINDS, it's the part where DELTA-STR is finally
computed.

Does that help?

Cheers,
Edi.