tclxml-users — Discussion on using the TclXML package

[Tclxml-users] Re: XML-RPC for Tcl problems

[Aaron S. <as...@sw...>]

Brian (bla...@hc...) wrote:

> I've grabbed Steve Ball's xmlrpc.tcl package, but I'm not having any luck
> getting it to talk to O'Reilly's Meerkat service.  I'd really appreciate some
> help.
> 
> I've written an extremely simple script

<snip />

> I get the following error when i try to execute it:

I think there might be a bug or two in the Tcl version. You want to try this
version with a few changes:

http://source.theinfo.org/myinfo/xmlrpc/xmlrpc.tcl

A quick diff is below. Be careful about line breaks.

    - [ Aaron Swartz | me...@aa... | http://www.aaronsw.com ]

--- BEGIN DIFF ---

$ diff -cb xmlrpc.tcl xmlrpc.tcl.1
*** xmlrpc.tcl  Tue Dec 12 08:56:32 2000
--- xmlrpc.tcl.1        Tue Dec 12 08:57:22 2000
***************
*** 383,389 ****
                }
                base64 {
                    # Supply a decoder?
-                   set result [dom::node cget [dom::node cget [dom::node
cget $node -firstChild] -firstChild] -nodeValue]
                }
                struct {
                    foreach member [dom::node children [dom::node cget $node
-firstChild]] {
--- 383,388 ----
***************
*** 420,437 ****
  
  proc xmlrpc::invoke xml  {
      set data [dom::DOMImplementation parse $xml]
-     
      dom::DOMImplementation trim $data
! #    set cleanup [list dom::DOMImplementation destroy $data]
!       set data [dom::document getElementsByTagName $data methodCall]
      set methodName [dom::node cget [dom::node cget \
            [lindex [dom::document getElementsByTagName $data methodName] 0]
\
            -firstChild] -nodeValue]
  
      set arguments {}
!     foreach parameter [dom::document getElementsByTagName \
!       [dom::document getElementsByTagName $data params] \
!     param] {
        lappend arguments [decodevalue [dom::node cget $parameter
-firstChild]]
      }
  
--- 419,433 ----
  
  proc xmlrpc::invoke xml  {
      set data [dom::DOMImplementation parse $xml]
      dom::DOMImplementation trim $data
!     set cleanup [list dom::DOMImplementation destroy $data]
! 
      set methodName [dom::node cget [dom::node cget \
            [lindex [dom::document getElementsByTagName $data methodName] 0]
\
            -firstChild] -nodeValue]
  
      set arguments {}
!     foreach parameter [dom::document getElementsByTagName $data param] {
        lappend arguments [decodevalue [dom::node cget $parameter
-firstChild]]
      }
  

--- END DIFF

For Steve, et al:

--- BEGIN ---

I've written an extremely simple script:
    package require xmlrpc
    set meerkat_server
"http://www.oreillynet.com/meerkat/xml-rpc/server.php"
    puts [xmlrpc::call $meerkat_server "meerkat.getChannelsByCategory" -int
2]


I get the following error when i try to execute it:

    XMLRPC_ERROR &#123;remote procedure call failed due to "can't read "":
no such variable"&#125;
        while executing
"callresponse $request"
        (procedure "xmlrpc::call" line 28)
        invoked from within
"xmlrpc::call $meerkat_server "meerkat.getChannelsByCategory" -int 2"
        (file "meerkat.tcl" line 8)

--- END ---

from http://www.xmlrpc.com/discuss/msgReader$1119

RE: [Tclxml-users] Problem with CharacterData

[Randy J. <rj...@ak...>]

Hi Steve,

Thanks for your prompt reply! I downloaded TclXML-2.0 and it worked much
better for me (in this application) than did TclXML-1.2.
There were still problems (different ones which may have been related to my
script), but I was able to work around them by using the "continue" Callback
Return Code to ignore the element which was giving me trouble.

Thanks Again,
Randy Jones


> -----Original Message-----
> From: Steve Ball [mailto:Ste...@zv...]
> Sent: Friday, December 08, 2000 5:49 PM
> To: rj...@ak...
> Cc: tcl...@li...
> Subject: Re: [Tclxml-users] Problem with CharacterData
>
>
> Randy Jones wrote:
> > I'm using TclXML-1.2 to parse a XML file which among other things
> > contains some C source code generated from a user interface
> > specification tool. Character data in the C source code appears to
> > have been properly processed so that C special characters do not
> > collide with XML special characters (e.g. "&" is converted
> to "amp").
> > This XML file is parsed cleanly by TclXML _without_ the C
> code in it.
> > With the C code in it, it can be parsed cleanly by XMLSpy editor.
> > There is a TclXML "Highlight.tcl" example I pulled off the
> web, it has
> > the same problem with the XML file in question that my script does.
> [...snip...]
>
> I'd suggest grabbing a copy of TclXML v2.0, preferably via NetCVS
> from the SourceForge repository.  V2.0 has various fixes for handling
> entities (pre-defined and otherwise).
>
> It is not surprising that 'highlight.tcl' encounters the same problem,
> since it is using the same underlying parser.
>
> If you have further problems, then please let me know.
>
> Cheers,
> Steve Ball
>
> --
> Steve Ball            | waX Me Lyrical XML Editor | Training
> & Seminars
> Zveno Pty Ltd         |     Web Tcl Complete      |      XML XSL
> http://www.zveno.com/ |      TclXML TclDOM        | Tcl, Web
> Development
> Ste...@zv...
> +---------------------------+---------------------
> Ph. +61 2 6242 4099   |   Mobile (0413) 594 462   | Fax +61 2
> 6242 4099
> _______________________________________________
> Tclxml-users mailing list
> Tcl...@li...
> http://lists.sourceforge.net/mailman/listinfo/tclxml-users
>

Re: [Tclxml-users] Problem with CharacterData

[Steve B. <Ste...@zv...>]

Randy Jones wrote:
> I'm using TclXML-1.2 to parse a XML file which among other things
> contains some C source code generated from a user interface
> specification tool. Character data in the C source code appears to
> have been properly processed so that C special characters do not
> collide with XML special characters (e.g. "&" is converted to "amp").
> This XML file is parsed cleanly by TclXML _without_ the C code in it.
> With the C code in it, it can be parsed cleanly by XMLSpy editor.
> There is a TclXML "Highlight.tcl" example I pulled off the web, it has
> the same problem with the XML file in question that my script does.
[...snip...]

I'd suggest grabbing a copy of TclXML v2.0, preferably via NetCVS
from the SourceForge repository.  V2.0 has various fixes for handling
entities (pre-defined and otherwise).

It is not surprising that 'highlight.tcl' encounters the same problem,
since it is using the same underlying parser.

If you have further problems, then please let me know.

Cheers,
Steve Ball

-- 
Steve Ball            | waX Me Lyrical XML Editor | Training & Seminars
Zveno Pty Ltd         |     Web Tcl Complete      |      XML XSL
http://www.zveno.com/ |      TclXML TclDOM        | Tcl, Web Development
Ste...@zv...  +---------------------------+---------------------
Ph. +61 2 6242 4099   |   Mobile (0413) 594 462   | Fax +61 2 6242 4099

[Tclxml-users] Problem with CharacterData

[Randy J. <rj...@ak...>]

Hi,
I'm using TclXML-1.2 to parse a XML file which among other things contains
some C source code generated from a user interface specification tool.
Character data in the C source code appears to have been properly processed
so that C special characters do not collide with XML special characters
(e.g. "&" is converted to "amp"). This XML file is parsed cleanly by TclXML
_without_ the C code in it. With the C code in it, it can be parsed cleanly
by XMLSpy editor. There is a TclXML "Highlight.tcl" example I pulled off the
web, it has the same problem with the XML file in question that my script
does.

When my script parses the XML file, I keep getting the error indicated in
the partial stack trace below. I've also included a fragment of the XML file
below. I've attempted to modify the sgml.tcl Entity and parseEvent routines
to work around this problem but without any success. Any suggestions are
greatly appreciated!

Thanks in Advance,
Randy Jones

Fragment of XML file where problem occurs.
---------------
...
<handler_list>
        <hd type="0" req_param_mask="0x00000001" opt_param_mask="0x00000000"
func="RCC_show_alarm_status">
extern RLSTATUS
RCC_show_alarm_status(cli_env *pCliEnv, paramList *pParams, sbyte *pAuxBuf)
{
    RLSTATUS    status = OK;
    sbyte       *pVal;
    paramDescr  *pParamDescr;
    sbyte    *pOutputBuf;
    Length   outputLen;

    /* get required parameter */
    status = RCC_DB_RetrieveParam(pParams, NULL, mShowAlarmStatus_NULL1,
&amp;pParamDescr );

the problem occurs when the parser processes the &amp field in the line
above.
    if ( OK != status )
    {
...

A partial stack trace is;
-------------
can't read "options(-statevariable)": no such variable
    while executing
"upvar #0 $options(-statevariable) state"
    (procedure "Entity" line 3)
    invoked from within
"Entity options {} ::::sgml::noop ::sgml::EntityPredef amp"
    (in namespace inscope "::sgml" script line 1)
    invoked from within
"namespace inscope ::sgml {Entity options {} ::::sgml::noop
::sgml::EntityPredef} {amp} "
    ("uplevel" body line 12)
    invoked from within
"uplevel #0 ::::sgml::noop {{
extern RLSTATUS
RCC_show_alarm_status(cli_env *pCliEnv, paramList *pParams, sbyte *pAuxBuf)
\\{
    RLSTATUS    status =..."
    ("eval" body line 1)
    invoked from within
"eval $text"
    (procedure "::sgml::parseEvent" line 326)
    invoked from within
"::sgml::parseEvent {?xml {} { version="1.0"?} {
.....End of Partial Stack Trace.
--------------------

[Tclxml-users] New XML Construct

[Steve B. <Ste...@zv...>]

New files have been checked in to both the tclxml and tcldom
modules.

The major addition is the new 'xmlswitch' package.  This package
provides two commands: 'xmlswitch::xmlswitch' and
'xmlswitch::domswitch'.
The reason for the redundancy is that I figure most people will
use 'namespace import' anyway.

This work is at a very early stage, and I am seeking comments and
suggestions on how these commands might be improved.

The 'xmlswitch' command aims to function in a way reminiscent
of the Tcl 'switch' command, except that an XML document is the
subject of the switch and the case labels are XPath location paths.
The script associated with each template is evaluated in the caller's
context when the location path matches.

For example:

xmlswitch <test><example/></test> {
    example[2] {
	puts "I found the second example element"
    }
    /test/example/text() {
	# Absolute path
    }
    * {
	puts "The default case"
    }
}

This should produce the output:

	The default case
	The default case

Case labels/script pairs are "templates", which is quite analogous
to XSLT.  It is also possible to specify the templates as multiple
arguments, to allow substitution:

xmlswitch {<test><example>Some text</example></test>} \
    example/text() {
	# Get the text
    } \
    {example[2]} {
	# Find the second example
    }

Notice how the second location path must be braced in this example.

The similarities to XSLT are only surface deep.  xmlswitch has quite
a different processing model.  Firstly, the XML document is parsed 
at command execution time and the templates matched as the parsing
occurs, ie sequentially.  The idea is to make this construct
suitable for processing large documents.  Unlike XSLT, every XML 
construct (start tags, character data, etc) is checked in document
order.  
Future versions will allow the template script to return a 'break' 
or 'continue' error code to alter the control flow.  At the moment
templates are matched when the start tag for an element occurs,
but one possible chnge is to allow end tags to match.

This command does a similar job to the 'xmlact' package used by
Ajuba2/Ajuba3[1].  The major differences are that 'xmlswitch' is a
single command, the complete XPath spec will be supported and
finally that 'xmlswitch' _does not_ extract data from the document.
To achieve the latter, the 'selectNode' and 'getStringValue' methods 
of the DOM package may be used (I haven't yet implemented the latter).
In combination, the facilities provided here should be more powerful 
than 'xmlact' (anyone have any comments on that?).

As the document is parsed a partial DOM tree is built.  The XPath
location paths are matched against this tree.  This means that
certain kinds of paths may not match as they would with XSLT;
namely those that look ahead in the tree.  For example 'example[simple]'
will not match, because the 'example' element occurs before 'simple'
in document order (but see above about matching end tags).  

If the '-async' option is given to xmlswitch, then the command returns 
a token which can be used to retrieve the DOM root node.  There will 
also be a facility for getting the DOM node which matches a template.
The '-async' also allows incremental parsing, which is obviously
very important when processing large documents.

The 'domswitch' command behaves very similarly to 'xmlswitch',
except that it takes a pre-built DOM tree as its argument.
In this case, all XPath location paths will match as expected.
I haven't implemented this command yet.

Enjoy,
Steve Ball

References
==========

[1] 'Scriptics Connect', E. Melski, S. Stanton, J. Ousterhout.
Proceedings of the 7th USENIX Tcl/Tk Conference.

-- 
Steve Ball            | waX Me Lyrical XML Editor | Training & Seminars
Zveno Pty Ltd         |     Web Tcl Complete      |      XML XSL
http://www.zveno.com/ |      TclXML TclDOM        | Tcl, Web Development
Ste...@zv...  +---------------------------+---------------------
Ph. +61 2 6242 4099   |   Mobile (0413) 594 462   | Fax +61 2 6242 4099

[Tclxml-users] Re: Xml Dom help

[Steve B. <Ste...@zv...>]

Dear Alex,

From the header it looks like you're using a very old version
of TclDOM.  I'd suggest you check out the latest version (2.0) from
the TclXML SourceForge project.  You'll need to use NetCVS to do that.

Version 2.0 has had a few patches applied to free up memory properly.

HTHs,
Steve Ball

You wrote:
> 
> hi there
> 
> I'm using the Dom.Tcl package of you
> 
> & I have encountered a strage Phenomenon, that is when I ask to free the
> Doom document from memory, it's not cleaning it as needed & the
> declarations & of the nodes stays in memory.
> 
> how can I delete all the document with  0KB  memory leak ?
> 
> thanks in advance
> 
> Alex Rakia
> 
> This is the header of the file :
> 
> #   the Document Object Model.  Support for the core specification
> #   is given here.  Layered support for specific languages,
> #   such as HTML and XML, will be in separate modules.
> #
> # Copyright (c) 1998 Zveno Pty Ltd
> # http://www.zveno.com/
> #
> # Zveno makes this software available free of charge for any purpose.
> # Copies may be made of this software but all of this notice must be
> included
> # on any copy.
> #
> # The software was developed for research purposes only and Zveno does not
> # warrant that it is error free or fit for any purpose.  Zveno disclaims
> any
> # liability for all claims, expenses, losses, damages and costs any user
> may
> # incur as a result of using, copying or modifying this software.
> #
> # $Id: dom.tcl,v 1.1 1998/08/14 00:03:59 steve Exp steve $

-- 
Steve Ball            | waX Me Lyrical XML Editor | Training & Seminars
Zveno Pty Ltd         |     Web Tcl Complete      |      XML XSL
http://www.zveno.com/ |      TclXML TclDOM        | Tcl, Web Development
Ste...@zv...  +---------------------------+---------------------
Ph. +61 2 6242 4099   |   Mobile (0413) 594 462   | Fax +61 2 6242 4099

[Tclxml-users] Push vs Pull

[Steve B. <Ste...@zv...>]

Dear All,

I've been doing some work on new commands for XML processing,
and the issue of push XML parsers versus pull XML parsers has
cropped up.  Please read the overview below, and let your thoughts
be known on whether this proposal would be worth the effort.

Currently, TclXML is mostly a push model parser.  The application feeds
the parser with data.  However, sometimes the parser will ask for
data, notably when an external entity reference is encountered.

In contrast, a pull model parser will ask for data when it becomes
starved of input to parse.  This might be a cleaner model to use,
because it would allow data from the document entity and external
entities to be treated the same way.  It may easier to control
reading data incrementally when the parser is being used by some
higher-level package (for example, TclDOM).

I shall propose a new option for TclXML: '-getdatacommand'.
The value for this option would be a Tcl script which returns
XML data.  This script is invoked when the parser requires more data.
When data is required for the current entity, no arguments are
appended.  If data is required from an external entity then the
public and system identifiers are appended as arguments.

An (incomplete) example:

set ch [open mydoc.xml]		;# this could be a socket...
fconfigure $ch -blocking no
fileevent $ch readable [list gotdata $ch]

set parser [xml::parser -getdatacommand [list pull $ch]]
$parser parse [read $ch] ;# we can supply initial data if available

proc pull {ch {publicid {}} {systemid {}}} {
    global dataAvailable

    switch -glob -- $publicid,$systemid {
        , {
            # Need to wait on input to be ready, check eof, etc.
            vwait ::dataAvailable
            return $dataAvailable
        }
        *, {
            # Public identifier only
        }
        ,* {
            # System identifier only
            set token [http::geturl $systemid]
            return [http::data $token]
        }
        default {
            # Both public and system identifier given
        }
    }
}

proc gotdata ch {
    global dataAvailable
    if {[eof $ch]} {
        close $ch
        set dataAvailable {not any more}
    } else {
        set dataAvailable [read $ch]
    }
}

-- 
Steve Ball            | waX Me Lyrical XML Editor | Training & Seminars
Zveno Pty Ltd         |     Web Tcl Complete      |      XML XSL
http://www.zveno.com/ |      TclXML TclDOM        | Tcl, Web Development
Ste...@zv...  +---------------------------+---------------------
Ph. +61 2 6242 4099   |   Mobile (0413) 594 462   | Fax +61 2 6242 4099

[Tclxml-users] XPath Support

[Steve B. <Ste...@zv...>]

Just checked in some new files and changes for both the TclXML
and TclDOM packages.  This is the start of adding XPath support.

In the TclXML package, added xpath.tcl.
Use it with 'package require xpath'.  It provides the command
xpath::split, which takes an XPath location path as an argument 
and parses it into its constituent location steps.  The result
is a Tcl list containing a number of sublists which have the
parts of the step.

For example:

xpath::split {/simple/example[2]}

would return:

{} {child simple {}} {child example { { 2 } }}

The first sublist is empty, indicating that this is an absolute
location path.  Each subsequent step is of the form
{axis node-test {?predicate ...?}}

NB. the abbreviated syntax has been expanded.

WARNING: This is only an initial implementation and the complete 
XPath syntax is certainly not yet supported, though that is 
the eventual aim.  At the moment simple steps and uncomplicated 
predicates (not containing a path expression themselves) work OK.

The TclDOM package has a new method for the 'DOMImplementation'
and 'node' commands: createNode.  Usage:

dom::DOMImplementation createNode $doc {simple/example[2]}
dom::node createNode $node {simple/example[2]/text()}

The difference between them is that former sets the document root
node as the initial context, whereas the latter sets the given node
as the initial context.

'createNode' will interpret the XPath path and walk the tree looking
for the deepest matching node.  If any nodes are missing along the
way they are created.  The deepest matching node is returned.
Obviously, not all XPath location paths are going to make sense
in this context.

TODO: a 'selectNode' method which will return all nodes matching
an XPath location path.

Also added is a new 'examples' directory.  There is one example
script, 'cgi2dom'.  This provides the command 'cgi2dom::createdocument'
which takes name-value pairs.  Names starting with '/' are interpreted
as XPath location paths and the 'createNode' method above is invoked
to construct the DOM tree.  The value is set as the string value of the
created node.  Other names are ignored.

The idea of this package is to allow an HTML fill-in form to
automagically create a DOM tree.  Eg.

<form action="createdoc.tml">
  Name: <input name="/person/name">
  Address: <input name="/person/address">

  <input type="submit" name="noeffect" value="Press Me">
</form>

createdoc.tml:

[set html {}

set doc [cgi2dom::createdocument [ncgi::nvlist]]

set html
]

<h1>Submission Accepted</h1>

Thanks!  Here's your XML document:

<pre>
[set xml [dom::DOMImplementation serialize $doc]
regsub -all < $xml {\&lt;} xml
regsub -all > $xml {\&gt;} xml
regsub -all & $xml {\&amp;} xml
set xml
]
</pre>

This should result in something looking like (modulo whitespace):

<person>
  <name>Steve Ball</name>
  <address>1 Markup Way, W3C-Ville</address>
</person>

Comments, suggestions, etc, are welcome.

Enjoy,
Steve Ball

-- 
Steve Ball            | waX Me Lyrical XML Editor | Training & Seminars
Zveno Pty Ltd         |     Web Tcl Complete      |      XML XSL
http://www.zveno.com/ |      TclXML TclDOM        | Tcl, Web Development
Ste...@zv...  +---------------------------+---------------------
Ph. +61 2 6242 4099   |   Mobile (0413) 594 462   | Fax +61 2 6242 4099

[Tclxml-users] Re: [tclxml] XSl Include

[Steve B. <Ste...@zv...>]

Please send all messages to tcl...@li...

Brian Thornton wrote:
> 
> Does anyone know how to do a include of a XSL file that has HTML in
> it like a menu bar>

XSL requires that its input be well-formed XML, so you can't feed
arbitrary HTML into XSL (you can HTML as the *output* of XSL, though).

If you want to process HTML using XSL you will have to fix the HTML.
Dave Raggett's Tidy program can do that, and a project has just started
to create a Tcl interface to Tidy (TclTidy?).

HTHs,
Steve Ball

-- 
Steve Ball            | waX Me Lyrical XML Editor | Training & Seminars
Zveno Pty Ltd         |     Web Tcl Complete      |      XML XSL
http://www.zveno.com/ |      TclXML TclDOM        | Tcl, Web Development
Ste...@zv...  +---------------------------+---------------------
Ph. +61 2 6242 4099   |   Mobile (0413) 594 462   | Fax +61 2 6242 4099

[Tclxml-users] TEST, please remove it.

[Moisei R. <mo...@cs...>]

Just a test.

-----------------------------------------------------------------
Rabinovich Moisei.
Gefen Dekel Technolgy.

[Tclxml-users] Test

[Steve B. <Ste...@zv...>]

Test posting

-- 
Steve Ball            | waX Me Lyrical XML Editor | Training & Seminars
Zveno Pty Ltd         |     Web Tcl Complete      |      XML XSL
http://www.zveno.com/ |      TclXML TclDOM        | Tcl, Web Development
Ste...@zv...  +---------------------------+---------------------
Ph. +61 2 6242 4099   |   Mobile (0413) 594 462   | Fax +61 2 6242 4099