// super-simple HTML tree with expandable/collapsible nodes
sclass HTMLTree {
  S headStuff() {
    ret loadJQuery2() + hcss([[
      .tree-toggler {
        display: inline-block;
        height: 1.3em;
        width: 0.7em;
        background: cornflowerblue;
        padding-left: 0.5em;
        padding-right: 0.5em;
        /*line-height: 50px; */
        text-align: center;
      }
      
      .tree-toggler a {
        text-decoration: none;
      }
    ]]) + hjs([[
      function tree_expandCollapse(id) {
        var children = $("#" + id);
        children.toggle();
        var vis = children.is(':visible');
        $("#" + id + "_toggle a").html(vis ? "–" : "+");
      }
    ]]);
  }
  
  S root(S contents) {
    ret ul(contents);
  }
  
  S node(S nodeHTML, S... children) {
    S id = aGlobalID();
    ret div(
      ahref_javascript(
        "tree_expandCollapse(" + jsQuote(id) + ");",
        "+"),
        class := "tree-toggler", id := id + "_toggle")
      + " " + nodeHTML
      + ul(asList(children), +id, style := "display: none");
  }
}