From thompdump at gmail.com  Thu Sep 16 23:28:19 2010
From: thompdump at gmail.com (David A. Thompson)
Date: Thu, 16 Sep 2010 16:28:19 -0700
Subject: [plexippus-xpath-devel] error with expression pointing to
	nonexistent child node
Message-ID: <4C92A813.6040900@gmail.com>

Depending on the xpath expression, when a match isn't found, either an 
empty node-set is returned or an error occurs. Is this deliberate?

1. Match works as expected:

TTEST> (xpath:evaluate "/etx" (cxml:parse "<etx></etx>" (stp:make-builder)))

#<XPATH:NODE-SET #.(ELEMENT LOCAL-NAME etx), ... {C9378D9}>


2. Evaluation of this xpath expression yields an empty node set:

TTEST> (xpath:evaluate "/foo" (cxml:parse "<etx></etx>" (stp:make-builder)))

#<XPATH:NODE-SET empty {CA0A879}>


3. Evaluation of this xpath expression triggers an error:

TTEST> (xpath:evaluate "//foo" (cxml:parse "<etx></etx>"
(stp:make-builder)))


Thanks for any suggestions...

- Alan




From ivan4th at gmail.com  Fri Sep 17 07:06:45 2010
From: ivan4th at gmail.com (Ivan Shvedunov)
Date: Fri, 17 Sep 2010 11:06:45 +0400
Subject: [plexippus-xpath-devel] error with expression pointing to
 nonexistent child node
In-Reply-To: <4C92A813.6040900@gmail.com>
References: <4C92A813.6040900@gmail.com>
Message-ID: <AANLkTin=cCPsq85_PzrWafLcW+JneGbhvq1yk8bSbPPS@mail.gmail.com>

Hello,

On Fri, Sep 17, 2010 at 3:28 AM, David A. Thompson <thompdump at gmail.com> wrote:
> Depending on the xpath expression, when a match isn't found, either an
> empty node-set is returned or an error occurs. Is this deliberate?
>
> 1. Match works as expected:
>
> TTEST> (xpath:evaluate "/etx" (cxml:parse "<etx></etx>" (stp:make-builder)))
>
> #<XPATH:NODE-SET #.(ELEMENT LOCAL-NAME etx), ... {C9378D9}>
>
>
> 2. Evaluation of this xpath expression yields an empty node set:
>
> TTEST> (xpath:evaluate "/foo" (cxml:parse "<etx></etx>" (stp:make-builder)))
>
> #<XPATH:NODE-SET empty {CA0A879}>
>
>
> 3. Evaluation of this xpath expression triggers an error:
>
> TTEST> (xpath:evaluate "//foo" (cxml:parse "<etx></etx>"
> (stp:make-builder)))
>

No, it should not signal an error when a match isn't found.
Which CL implementation are you using? (looks like SBCL?)
I cannot reproduce this problem, what does the backtrace look like?

-- 
Ivan Shvedunov <ivan4th at gmail.com>
;; My GPG fingerprint is: 2E61 0748 8E12 BB1A 5AB9? F7D0 613E C0F8 0BC5 2807



From thompdump at gmail.com  Fri Sep 17 20:17:00 2010
From: thompdump at gmail.com (David A. Thompson)
Date: Fri, 17 Sep 2010 13:17:00 -0700
Subject: [plexippus-xpath-devel] error with expression pointing to
 nonexistent child node
In-Reply-To: <AANLkTin=cCPsq85_PzrWafLcW+JneGbhvq1yk8bSbPPS@mail.gmail.com>
References: <4C92A813.6040900@gmail.com>
	<AANLkTin=cCPsq85_PzrWafLcW+JneGbhvq1yk8bSbPPS@mail.gmail.com>
Message-ID: <4C93CCBC.50307@gmail.com>

On 09/17/2010 12:06 AM, Ivan Shvedunov wrote:
> Hello,
>
> On Fri, Sep 17, 2010 at 3:28 AM, David A. Thompson<thompdump at gmail.com>  wrote:
>> Depending on the xpath expression, when a match isn't found, either an
>> empty node-set is returned or an error occurs. Is this deliberate?
>>
>> 1. Match works as expected:
>>
>> TTEST>  (xpath:evaluate "/etx" (cxml:parse "<etx></etx>" (stp:make-builder)))
>>
>> #<XPATH:NODE-SET #.(ELEMENT LOCAL-NAME etx), ... {C9378D9}>
>>
>>
>> 2. Evaluation of this xpath expression yields an empty node set:
>>
>> TTEST>  (xpath:evaluate "/foo" (cxml:parse "<etx></etx>" (stp:make-builder)))
>>
>> #<XPATH:NODE-SET empty {CA0A879}>
>>
>>
>> 3. Evaluation of this xpath expression triggers an error:
>>
>> TTEST>  (xpath:evaluate "//foo" (cxml:parse "<etx></etx>"
>> (stp:make-builder)))
>>
>
> No, it should not signal an error when a match isn't found.
> Which CL implementation are you using? (looks like SBCL?)
> I cannot reproduce this problem, what does the backtrace look like?
>

Ivan,

Thanks for the quick response. I'm using SBCL 1.0.39.

SBCL's complaint:

The value NIL is not of type VECTOR.
    [Condition of type TYPE-ERROR]

Restarts:
  0: [RETRY] Retry SLIME REPL evaluation request.
  1: [*ABORT] Return to SLIME's top level.
  2: [TERMINATE-THREAD] Terminate this thread (#<THREAD 
"new-repl-thread" RUNNING {C2A3F81}>)

Backtrace:
   0: (CXML-STP-IMPL::NORMALIZE-TEXT-NODES! #.(CXML-STP:ELEMENT #| 
:PARENT of type DOCUMENT |# :LOCAL-NAME "etx"))
   1: ((SB-PCL::FAST-METHOD XPATH-PROTOCOL:CHILD-PIPE-USING-NAVIGATOR 
((EQL :DEFAULT-NAVIGATOR) CXML-STP:ELEMENT)) ..)
   2: ((LAMBDA (XPATH::NODE XPATH::STARTING-NODE)) ..)
   3: ((LAMBDA (XPATH::N)) #.(CXML-STP:ELEMENT #| :PARENT of type 
DOCUMENT |# :LOCAL-NAME "etx"))
   4: (XPATH::MAPPEND-PIPE #<CLOSURE (LAMBDA #) {C2B8425}> 
(#.(CXML-STP:ELEMENT #| :PARENT of type DOCUMENT |# :LOCAL-NAME "etx") . 
#<CLOSURE # {C2B84FD}>))
   5: (XPATH::MAPPEND-PIPE #<CLOSURE (LAMBDA #) {C2B8425}> 
(#.(CXML-STP-IMPL::DOCUMENT :CHILDREN '(#1=#.(CXML-STP:ELEMENT #| 
:PARENT of type DOCUMENT |# :LOCAL-NAME "etx"))) #1# . #<CLOSURE # 
{C2B84FD}>))
   6: ((LAMBDA (XPATH::NODE XPATH::STARTING-NODE)) ..)
   7: ((LAMBDA (XPATH::N)) #.(CXML-STP-IMPL::DOCUMENT :CHILDREN 
'(#.(CXML-STP:ELEMENT #| :PARENT of type DOCUMENT |# :LOCAL-NAME "etx"))))
   8: (XPATH::MAPPEND-PIPE #<CLOSURE (LAMBDA #) {C2B83C5}> 
(#.(CXML-STP-IMPL::DOCUMENT :CHILDREN '(#.(CXML-STP:ELEMENT #| :PARENT 
of type DOCUMENT |# :LOCAL-NAME "etx"))) . #<CLOSURE # {C2B83A5}>))
   9: ((LAMBDA (XPATH::NODE XPATH::STARTING-NODE)) ..)
  10: ((LAMBDA (XPATH:CONTEXT)) #<XPATH:CONTEXT {C2B8361}>)
  11: (XPATH:EVALUATE-COMPILED #<CLOSURE (LAMBDA #) {C2B8355}> 
#.(CXML-STP-IMPL::DOCUMENT :CHILDREN '(#.(CXML-STP:ELEMENT #| :PARENT of 
type DOCUMENT |# :LOCAL-NAME "etx"))) NIL)
  12: (SB-INT:SIMPLE-EVAL-IN-LEXENV (XPATH:EVALUATE "//foo" (CXML:PARSE 
"<etx></etx>" (CXML-STP:MAKE-BUILDER))) #<NULL-LEXENV>)
  --more--



From ivan4th at gmail.com  Fri Sep 17 20:26:09 2010
From: ivan4th at gmail.com (Ivan Shvedunov)
Date: Sat, 18 Sep 2010 00:26:09 +0400
Subject: [plexippus-xpath-devel] error with expression pointing to
 nonexistent child node
In-Reply-To: <4C93CCBC.50307@gmail.com>
References: <4C92A813.6040900@gmail.com>
	<AANLkTin=cCPsq85_PzrWafLcW+JneGbhvq1yk8bSbPPS@mail.gmail.com>
	<4C93CCBC.50307@gmail.com>
Message-ID: <AANLkTim=yuT2-ejxp1fMGiOANJf1b_vSChXxLdkBLB1S@mail.gmail.com>

Hello,

On Sat, Sep 18, 2010 at 12:17 AM, David A. Thompson <thompdump at gmail.com> wrote:

> Ivan,
>
> Thanks for the quick response. I'm using SBCL 1.0.39.
>
> SBCL's complaint:
>
> The value NIL is not of type VECTOR.
> ? [Condition of type TYPE-ERROR]
>
> Restarts:
> ?0: [RETRY] Retry SLIME REPL evaluation request.
> ?1: [*ABORT] Return to SLIME's top level.
> ?2: [TERMINATE-THREAD] Terminate this thread (#<THREAD "new-repl-thread"
> RUNNING {C2A3F81}>)
>
> Backtrace:
> ?0: (CXML-STP-IMPL::NORMALIZE-TEXT-NODES! #.(CXML-STP:ELEMENT #| :PARENT of
> type DOCUMENT |# :LOCAL-NAME "etx"))
> ?1: ((SB-PCL::FAST-METHOD XPATH-PROTOCOL:CHILD-PIPE-USING-NAVIGATOR ((EQL
> :DEFAULT-NAVIGATOR) CXML-STP:ELEMENT)) ..)
> ?2: ((LAMBDA (XPATH::NODE XPATH::STARTING-NODE)) ..)
> ?3: ((LAMBDA (XPATH::N)) #.(CXML-STP:ELEMENT #| :PARENT of type DOCUMENT |#
> :LOCAL-NAME "etx"))
> ?4: (XPATH::MAPPEND-PIPE #<CLOSURE (LAMBDA #) {C2B8425}>
> (#.(CXML-STP:ELEMENT #| :PARENT of type DOCUMENT |# :LOCAL-NAME "etx") .
> #<CLOSURE # {C2B84FD}>))
> ?5: (XPATH::MAPPEND-PIPE #<CLOSURE (LAMBDA #) {C2B8425}>
> (#.(CXML-STP-IMPL::DOCUMENT :CHILDREN '(#1=#.(CXML-STP:ELEMENT #| :PARENT of
> type DOCUMENT |# :LOCAL-NAME "etx"))) #1# . #<CLOSURE # {C2B84FD}>))
> ?6: ((LAMBDA (XPATH::NODE XPATH::STARTING-NODE)) ..)
> ?7: ((LAMBDA (XPATH::N)) #.(CXML-STP-IMPL::DOCUMENT :CHILDREN
> '(#.(CXML-STP:ELEMENT #| :PARENT of type DOCUMENT |# :LOCAL-NAME "etx"))))
> ?8: (XPATH::MAPPEND-PIPE #<CLOSURE (LAMBDA #) {C2B83C5}>
> (#.(CXML-STP-IMPL::DOCUMENT :CHILDREN '(#.(CXML-STP:ELEMENT #| :PARENT of
> type DOCUMENT |# :LOCAL-NAME "etx"))) . #<CLOSURE # {C2B83A5}>))
> ?9: ((LAMBDA (XPATH::NODE XPATH::STARTING-NODE)) ..)
> ?10: ((LAMBDA (XPATH:CONTEXT)) #<XPATH:CONTEXT {C2B8361}>)
> ?11: (XPATH:EVALUATE-COMPILED #<CLOSURE (LAMBDA #) {C2B8355}>
> #.(CXML-STP-IMPL::DOCUMENT :CHILDREN '(#.(CXML-STP:ELEMENT #| :PARENT of
> type DOCUMENT |# :LOCAL-NAME "etx"))) NIL)
> ?12: (SB-INT:SIMPLE-EVAL-IN-LEXENV (XPATH:EVALUATE "//foo" (CXML:PARSE
> "<etx></etx>" (CXML-STP:MAKE-BUILDER))) #<NULL-LEXENV>)
> ?--more--
>

Seems like this is CXML-STP whitespace normalization bug which
is already fixed in its git repository. Try it with the fresh version:
git clone http://www.lichteblau.com/git/cxml-stp.git

-- 
Ivan Shvedunov <ivan4th at gmail.com>
;; My GPG fingerprint is: 2E61 0748 8E12 BB1A 5AB9? F7D0 613E C0F8 0BC5 2807



From david at lichteblau.com  Fri Sep 17 20:19:55 2010
From: david at lichteblau.com (David Lichteblau)
Date: Fri, 17 Sep 2010 22:19:55 +0200
Subject: [plexippus-xpath-devel] error with expression pointing to
 nonexistent child node
In-Reply-To: <4C93CCBC.50307@gmail.com>
References: <4C92A813.6040900@gmail.com>
	<AANLkTin=cCPsq85_PzrWafLcW+JneGbhvq1yk8bSbPPS@mail.gmail.com>
	<4C93CCBC.50307@gmail.com>
Message-ID: <20100917201955.GA9830@radon>

Quoting David A. Thompson (thompdump at gmail.com):
> Ivan,
> 
> Thanks for the quick response. I'm using SBCL 1.0.39.
> 
> SBCL's complaint:
> 
> The value NIL is not of type VECTOR.
>     [Condition of type TYPE-ERROR]

This sounds like a recently fixed bug in cxml-stp, which occured with
current SBCL.

Try upgrading your cxml-stp from git.


Thanks
d.