XML: Bubble Sort utilizing XMLVARs

Recently, a question about sorting has come up. The context was an ICAO Search of Facility types which returns ICAO strings in alphabetical order. However, each ICAO represents a Facility that has a certain distance from the user's aircraft, and a sort according to distance is needed.

Acknowledgements are owed to Robbie McElrath who hammered out the Bubble Sort XML in a few minutes (thank you, Robbie) and Tom Aguilo, for providing XMLVARs. The sort script that follows makes use of the array-forming capabilities of XMLVARS. Thanks, Tom.

 MACROS:
   <Macro Name="sort">
     @2 (>L:sort_len, number)
     :127
        0 (>L:sort_swapped, bool)
        0 sp0
        :128
           l0 ++ s0 (L:sort_len, number) >= if{ g129 }
           @1 l0 -- scat s10 (>C:XMLVARS:SearchVarName, string) (C:XMLVARS:NumberValue, number) s11
           @1 l0    scat     (>C:XMLVARS:SearchVarName, string) (C:XMLVARS:NumberValue, number) s12 >
               if{
                 l11 (>C:XMLVARS:NumberValue, number)
                 l10 (>C:XMLVARS:SearchVarName, string) l12 (>C:XMLVARS:NumberValue, number)
                 1 (>L:sort_swapped, bool)
               }
           g128
        :129
        (L:sort_swapped, bool) if{ g127 }
   </Macro>
   
   <Macro Name="store">
     @1 @2 scat (>C:XMLVARS:StoreVarName, string) (>C:XMLVARS:NumberValue, number)
   </Macro>  

 UPDATE:
   <Update Frequency="18" Hidden="No">      
   (L:SortInit, bool) 0 ==
       if{
           2 @store('sort_test', 0)
           1 @store('sort_test', 1)
           4 @store('sort_test', 2)
           8 @store('sort_test', 3)
           7 @store('sort_test', 4)
           0 @store('sort_test', 5)
           1 (>L:SortInit, bool)
       }  
                  
       'sort_test0' (>C:XMLVARS:SearchVarName,string) (C:XMLVARS:NumberValue,number) (>L:SortTest0, number)       
       'sort_test1' (>C:XMLVARS:SearchVarName,string) (C:XMLVARS:NumberValue,number) (>L:SortTest1, number)  
       'sort_test2' (>C:XMLVARS:SearchVarName,string) (C:XMLVARS:NumberValue,number) (>L:SortTest2, number)  
       'sort_test3' (>C:XMLVARS:SearchVarName,string) (C:XMLVARS:NumberValue,number) (>L:SortTest3, number)  
       'sort_test4' (>C:XMLVARS:SearchVarName,string) (C:XMLVARS:NumberValue,number) (>L:SortTest4, number)  
       'sort_test5' (>C:XMLVARS:SearchVarName,string) (C:XMLVARS:NumberValue,number) (>L:SortTest5, number)  
   </Update>

 MOUSE:
   <Area Left="150" Top="130" Width="16" Height="16">
       <Cursor Type="Hand" />
           <Click Kind="LeftSingle+RightSingle">
               (L:SortMacroExecuted,enum) ++ (>L:SortMacroExecuted,enum)
               @sort('sort_test', 6)
           </Click>
   </Area>    

Notes:

- (L:sort_len, number) is the array length. For example, IcaoSearchMatchedIcaosNumber

- The SortInit sequence was used for testing purposes only. It stores 2, 1, 4, 8, 7, and 0 into XMLVARs named 'sort_test0' through 'sort_test5'. In a real application, GeoCalcDistance information would actually generate the values to be stored in these XMLVARs and a SortInit sequence would probably never be needed.

- The bottom 6 lines in the Update section simply read the XMLVARs and store then into traditional L:Vars so that BlackBox can display them (so you can see what is happening before and after the sort is applied)

- A Mouse Area 'click area' is used to execute the sort macro, @sort('sort_test', 6). The number 6 is the array length to be sorted. In the real example I postulated, it would be written @sort('sort_test',C:fs9gps:IcaoSearchMatchedIcaosNumber)