FWIW, YAZ CQL parser produces similar result, except that prefix
<name></name>
is not present.

I expect there would be other areas where result would not be similar.
For example:

[email protected]:~/proj/yaz/test$ ../util/cql2xcql
 >dc="first" >dc="second" dc.title=x
<searchClause>
   <prefixes>
     <prefix>
       <identifier>second</identifier>
     </prefix>
   </prefixes>
   <index>title</index>
   <relation>
     <value>=</value>
   </relation>
   <term>x</term>
</searchClause>

YAZ CQL parser always try to _resolve_ the prefixes. And prefixes only
occur in <searchClause> and nowhere else. In other words, prefixes only
occur at leaves in the parse tree.

For example:
[email protected]:~/proj/yaz/test$ ../util/cql2xcql
 >p1 (f=a and f=b)
<triple>
   <boolean>
     <value>and</value>
   </boolean>
   <leftOperand>
     <searchClause>
       <prefixes>
         <prefix>
           <identifier>p1</identifier>
         </prefix>
       </prefixes>
       <index>f</index>
       <relation>
         <value>=</value>
       </relation>
       <term>a</term>
     </searchClause>
   </leftOperand>
   <rightOperand>
     <searchClause>
       <prefixes>
         <prefix>
           <identifier>p1</identifier>
         </prefix>
       </prefixes>
       <index>f</index>
       <relation>
         <value>=</value>
       </relation>
       <term>b</term>
     </searchClause>
   </rightOperand>
</triple>

The reason for choosing this route, is that a backend (CQL-to-something)
then don't have to do prefix-to-identifier resolving.

/ Adam

Robert Sanderson wrote:
>> In the past I have found that this query is legal and very ugly:
>>  prox and/or <dc:title>and or</dc:title> and or
>
>
> Here's the equally ugly XCQL output from my parser:
>
> <triple xmlns="http://www.loc.gov/zing/cql/xcql/">
>   <boolean>
>     <value>and</value>
>     <modifiers>
>       <modifier>
>         <type>or</type>
>         <comparison>&lt;</comparison>
>         <value>dc:title</value>
>       </modifier>
>     </modifiers>
>   </boolean>
>   <leftOperand>
>     <searchClause>
>       <index>cql.serverchoice</index>
>       <relation>
>         <value>scr</value>
>       </relation>
>       <term>prox</term>
>     </searchClause>
>   </leftOperand>
>   <rightOperand>
>     <searchClause>
>       <prefixes>
>         <prefix>
>           <name></name>
>           <identifier>and</identifier>
>         </prefix>
>       </prefixes>
>       <index>or</index>
>       <relation>
>         <value>&lt;</value>
>         <modifiers>
>           <modifier>
>             <type>dc:title</type>
>             <comparison>&gt;</comparison>
>             <value>and</value>
>           </modifier>
>         </modifiers>
>       </relation>
>       <term>or</term>
>     </searchClause>
>   </rightOperand>
> </triple>
>
>
>       ,'/:.          Dr Robert Sanderson ([log in to unmask])
>     ,'-/::::.        http://www.o-r-g.org/~azaroth/
>   ,'--/::(@)::.      Dept. of Computer Science, Room 805
> ,'---/::::::::::.    University of Liverpool
> ____/:::::::::::::.  L5R Shop: http://www.cardsnotwords.com/
> I L L U M I N A T I
>