%{ showchildren.i   recursive function to display category navigation

   Invoked as:
      @show_children (ctable, cgmenbr, parent, mycat, "0", "0")

   Parameters (global variables)
      ctable     (in) table of category info, provided by fill_ctable()
      parent     (in) display child categories of this parent ref #
      mycat      (in) targeted category -- show with arrow
      cgmenbr    (in) merchant number
      "0"s            provides placeholder for local variables i and x.

   Purpose:
      Provide a recursive function to display the exploded left-bar 
      navigation tree of the product categories.

   How it works:
      The pseudo-code version (in a language with params and local vars)
      looks like:
         function show_children (table, parent, mycat) {
            for all x, where parent_of(x) == parent {
               display category x
               if x is any_parent_of (mycat)  show_children (table, x, mycat)
            }
         }

   Notes & Bugs:
      This code requires Net.Data version 6.1.1.1; earlier versions do
      not properly support parameters and recursion.

      Since Net.Data does not support any direct definition of local
      variables, they must be "faked" by supplying non-functional
      arguments which can then be used as local variables.  Hence the
      trailing "0"s, which become i and x, respectively.

   History of revisions:
   +CR 11/13/00 11:14 New script.
   +CR 11/26/00 11:14 Updated for Net.Data 6.1.1.1 support.
========================================================================%}

%{---any_parent_of() is a recursive service function, used
     only by show_children(), that determines if x is the same as
     cat, a parent of cat, a g'parent of cat... etc. %}
%macro_function any_parent_of (OUT success, IN ctable, IN x, IN cat) {
   %if (x == cat)
      @dtw_assign (success, "1")
   %else
   
      %{---returns index cx of cat in ctable. %}
      @ctable_index (cx, ctable, cat, "0")
   
      %{---if   ctable[cx,4] == x    return true %}
      %if   (@dtw_tb_rgetv (ctable, cx, "4") == x)
         @dtw_assign (success, "1")
   
      %{---elif ctable[cx,4] == ""   return false %}
      %elif (@dtw_tb_rgetv (ctable, cx, "4") == "")
         @dtw_assign (success, "0")
   
      %{---else  cat = ctable[cx, 1];   return any_parent_of()  %}
      %else
         @any_parent_of (success, ctable, x, @dtw_tb_rgetv (ctable, cx, "4"))
      %endif
   %endif
%}

%macro_function show_children (IN ctable, IN cgmenbr, IN parent, IN mycat,
                               IN i, IN x) {

   %{---Indentation of "exploded" view is handled by tables within tables... %}
   <TABLE BORDER=0 CELLSPACING=0 CELLPADDING=0>

   %{---For x, in children of parent... %}
   @dtw_assign (i, "1")
   %while (i <= @dtw_tb_rrows(ctable)) {
      %if (@dtw_tb_rgetv (ctable, i, "4") == parent)
         @dtw_assign (x, @dtw_tb_rgetv (ctable, i, "1"))

         %{---Display category x. %}
         <TR VALIGN=top>
         %if (x == mycat)
            <TD><span class="sidenavs"
             ><nobr>&nbsp;<IMG SRC="/danly/misc/arrow.gif" ALT="&gt;"
             ></nobr></span></TD>
         %else
            <TD><span class="sidenavs"
             >&nbsp;<IMG SRC="/danly/misc/clearpix.gif" ALT=" "
                            WIDTH=10 HEIGHT=1></span></TD>
         %endif

         @dtw_assign (text, @dtw_tb_rgetv(ctable, i, "2"))
         <TD><span class="sidenavs"><a 
 href="/webapp/commerce/command/CategoryDisplay?cgrfnbr=$(x)&cgmenbr=$(cgmenbr)"
           class="noUL">$(text)</a></span>

         %{---If x is any parent of mycat, call show_children recursively
              on x. %}
         @any_parent_of (success, ctable, x, mycat)
         %if (success == "1")
            @show_children (ctable, cgmenbr, x, mycat, "0", "0")
         %endif
         </TD>

      %endif
      @dtw_add (i, "1", i)
   %}
   </TABLE>
%}