$ // Whether to do DAG(tree) or not 
$ param type = 'simple' 

$ ecmascript
  function check (tree, name)
  {
    var t = '_' + tree + '_';
    return t.indexOf('_' + name + '_') == -1;
  }

  var da = new Array();
  function not_done(name)
  {
    if ( da[name] ) return false;
    da[name] = true;
    return true;
  }
$ end ecmascript

$ // This is a recursive template applied on productions 
$ template tree(prod = '')
  $prod [shape=diamond,label="@name"]
$   foreach {alt}
$     set alt = {concat($prod,'_alt_',@ename)}
  $alt [shape=box,label="${../@name}.@name"]
  $prod -> $alt
$     foreach enode in {elem}
$       set elem = {concat($alt,'_',@ename)}
$       if {@is_token}
  $alt -> $elem [label="@name@modifier"]
  $elem [shape=ellipse,label="@type"]
$       else
$         if {sablecc:check(string($prod), string(@etype))}
$           foreach {//production[@ename=$enode/@etype]}
$             set subtree = {concat($elem,'_',@ename)}
  $alt -> $subtree [label="@name@modifier"]
$             call tree(prod = $subtree)
$           end
$         else
  $alt -> $elem [label="@name@modifier"]
  $elem [shape=triangle,label="@type"]
$         end if
$       end if
$     end foreach
$   end foreach
$ end template

$ template simple(prod = '')
  $prod [shape=diamond,label="@name"]
$   foreach {alt}
$     set alt = {concat($prod,'_alt_',@ename)}
  $alt [shape=box,label="${../@name}.@name"]
  $prod -> $alt
$     foreach enode in {elem}
$       set elem = {concat($alt,'_',@ename)}
$       if {@is_token}
  $alt -> $elem [label="@name@modifier"]
  $elem [shape=ellipse,label="@type"]
$       else
$         if {sablecc:not_done(string(@etype))}
$           set subtree = {concat($elem,'_',@ename)}
  $alt -> $subtree [label="@name@modifier"]
$           foreach {//production[@ename=$enode/@etype]}
$             call simple(prod = $subtree)
$           end
$         else
  $alt -> $elem [label="@name@modifier"]
  $elem [shape=triangle,label="@type"]
$         end if
$       end if
$     end foreach
$   end foreach
$ end template

digraph mygraph {
$ choose
$   when {$type='simple'}
$     foreach {//production[position()=1]}
$       call simple(prod = @ename)
$     end foreach
$   end when
$   when {$type='tree'}
$     foreach {//production[position()=1]}
$       call tree(prod = @ename)
$     end foreach
$   end when
$   when {$type='graph'}
$     foreach {//production}
  @ename [shape=diamond,label="@name"]
$       foreach {alt}
  @ename [shape=box,label="${../@name}.@name"]
  ${../@ename} -> @ename
$         foreach {elem}
  ${../@ename} -> @etype [label="@name@modifier"]
$           if {@is_token}
  @etype [shape=ellipse,label="@type"]
$           end if
$         end foreach
$       end foreach
$     end foreach
$     end when
$ end choose
}