That makes life a lot easier!

The only caveat I can think of is the refas plugin ie :

(refas tag="user")/path/to/user.xml(/refas)

<p>Welcome back <user>username</user>, you were last here on : [time f
+ormat="HH:MM:SS, DD/MM/YYY"]<user>lastvisit</user>[/time].</p>
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Where <user> is not a known tag until refas creates a definition for it which maps the user tag data to the nodes in the user.xml file, and [time] takes an integer and gives back a formatted date/time string.

I was planning on expressing the difference between the three tag types by adding an attribute called aXML_class to the tags when converting them to standard XML :

  (SQL mode="mask")
    <query>
  
       SELECT username,email FROM users;

    </query>
    <mask>

      [link action="showuser" 
          username="<d>username</d>"
          ]<d>username</d>[/link],

      [link to="mailto:<d>email</d>"]<d>email</d>[/link] 
      <br>
  
    </mask>
  (/SQL)
  
Becomes :

 <SQL aXML_class="primary" mode="mask">
    <query>
  
       SELECT username,email FROM users;

    </query>
    <mask>

      <link aXML_class="tertiary"
            action="showuser" 
          username="<d>username</d>"
          ><d>username</d></link>,

      <link aXML_class="tertiary" 
                     to="mailto:<d>email</d>"
          ><d>email</d></link> 
      <br>
  
    </mask>
  </SQL>
  
Also when tags have tags embedded in their attributes like this :

<a b="<c>d</c>">data</a>

converting the expression to XML like this;

<a aXML_class="standard">
  <attr>b="<c aXML_class="standard">d</c>"</attr>
  <contents>data</contents>
</a>
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The examples above would map like this :

<SQL aXML_class="primary" mode="mask">
    <query>
  
       SELECT username,email FROM users;

    </query>
    <mask>

      <link aXML_class="tertiary" action="showuser" username="<d>usern
+ame</d>"><d>username</d></link>,

      <link aXML_class="tertiary" to="mailto://<d>email</d>"><d>email<
+/d></link> 
      <br>
  
    </mask>
  </SQL>
 
becomes :

my @nodes = ( Node->new( SQL => { aXML_class => 'primary',
                                        attr => { mode  => "mask" },
                                    contents => { '<query>SELECT * FRO
+M users</query>
                                                   <mask>',
                                                   
                                                     [ Node->new( link
+ => { aXML_class => 'tertiary',
                                                                      
+            attr  => { action => 'showuser',
                                                                      
+         username => '<d>username<d>' },
                                                                      
+         contents => '<d>username</d>'
                                                                      
+          } ),
                                                                      
+                                                                     
+                   contents => '<d>username</d>' } ),
                                                       Node->new( link
+ => { aXML_class => 'tertiary',
                                                                      
+           attr  => { to => 'mailto://<d>email</d>' },
                                                                      
+        contents => '<d>email</d>'
                                                                      
+     } ),
                                                    
                                                     ],
                                                  '<br></mask>'
  
                                                }
                                 } )
             );   


and

<a b="<c>d</c>">data</a>

becomes :

<a aXML_class="standard">
  <attr>b="<c aXML_class="standard">d</c>"</attr>
  <contents>data</contents>
</a>

then becomes :

my @nodes = ( Node->new( a => { aXML_class => 'standard',
                                      attr => { b => Node->new ( c => 
+{ aXML_class => 'standard', 
                                                                      
+    contents => 'd'
                                                                      
+ }
                                                                )
                                              },
                                  contents => 'data' }
                              }
                        )
             );
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