[Tclxml-users] TclXML confusions (was: How can I ensure that I always have a list?)

[Cameron L. <cl...@la...>]

In article <jij...@la...>, I recommended:
>In article <116...@h5...>,
>comp.lang.tcl <phi...@gm...> wrote:
>			.
>			.
>			.
>>> What exactly are you attempting to do?
>>
>>It's so easy.  All I want to do is convert an XML file into a TCL list,
>>that's it, just a TCL list:
>>
>>attr1 {val1} attr2 {val2}
>			.
>			.
>			.
>Should we recommend a SAX or XQuery approach for this?
>A SAX accumulator used to be canonical for something
>this simple; I haven't worked with Rolf's XPath, but I
>suspect it affords a one-liner that satisfies the
>requirements.

Oh, my; I *do* perceive deficiencies in TclXML documentation.

I know that TclXML has had XPath since 2001.  In particular, by 2004,
Steve wrote about selectNodes in 3.0 <URL:
http://talkaboutprogramming.com/group/comp.lang.tcl/messages/253140.html >.
When I run

  puts [package require dom]

  set xml_image {<?xml version = "1.0" encoding = "UTF-8" ?>
  <via id="1" trivia_id="255" question="How much wood would a
     woodchuck chuck?" answer_id="1" answer="A lot"
     expDate="116494926"></via>
  }

  set doc [dom::parse $xml_image]
  set nodes [$doc selectNodes //via]

on a recent Mac OS, though, I see 

  3.1 
  bad method "selectNodes": must be cget, configure, createElement,
      createDocumentFragment, createTextNode, createComment,
      createCDATASection, createProcessingInstruction, createAttribute,
      createEntity, createEntityReference, createDocTypeDecl, importNode,
      createElementNS, createAttributeNS, getElementsByTagNameNS,
      getElementsById, createEvent, getElementsByTagName, dtd, or schema

So:  what's it take to get TclXML to do XPath?