$ids=0
def color_by(color,text)
  "<span style=\"color:#{color}\">#{text}</span>"
end
def highligh(id,text)
  "<span onmouseover='document.getElementById(\"id#{id}\").style.background=\"#002020\";'
         onmouseout ='document.getElementById(\"id#{id}\").style.background=\"none\";'>#{text}</span>"
end
def highlighted(id,text)
  "<span id=id#{id}>#{text}</span>"
end
amethyst AST2Amethyst {
  trans = Or[  trans*:ary  ]            ->     ary*"|"
        | Seq[ trans*:ary  ]            ->     ary*" "
        | Apply[ .:name ]               -> name
        | Bind[ trans:expr @name:name ] -> "("+expr+"):"+name[0]
}

amethyst Syntax_Highligth {
  root = ( Grammar[  @rules=>[rule*]:rules -> "amethyst #{@name} < #{@parent} {\n #{rules*""} }"
           ] | .)*:{it*""}
  
  rule = Rule[  {@body}=>trans:body  -> "#{@name} = #{body}\n"
             ]

  trans = Or_AST[  trans*:ary  ]        {
 $ids+=1;highlighted($ids,"#{ary*highligh($ids,"|")}")
}
        | Append_AST[ (@exp=>trans):expr @name:name]  -> "#{expr}#{color_by("red",":[#{name[0]}]")}"
        | Parenthesis[ trans:t ]           -> $ids+=1; highlighted($ids,highligh($ids,"(")+t+ highligh($ids,")"))
        | Seq[ trans*:ary  ]               -> " #{ary*" "} "
        | Act[ Args[.*:ary]      ]         -> color_by("brown","{#{ary*""}}")
        | CAct[ .* ]                       -> "" 
        |  Pass_AST[ @from=>trans:from @to=>trans:to ] -> highlighted($ids+=1, from + highligh($ids,color_by("yellow","=>")) + to)
        | Enter_AST[ @from=>trans:from @to=>trans:to ] -> highlighted($ids+=1, from + highligh($ids,color_by("yellow","[")) + to + highligh($ids,color_by("yellow","]")))

        | Comment[ .:text ]                -> "##{text}"
        | Apply[ [ "seq" ] CAct[.:str] ]   ->  "'#{str.inspect[1...-1]}'"
        | Apply[ ["token"] CAct[.:str] ]   -> "\"#{str.inspect[1...-1]}\""
        | Apply[ ["regch"]  Act[.:str] ]   -> "&lt;#{str[2...-2]}&gt;"
        | Apply[ ["anything"]          ]   -> "."

        | Apply[ .:name trans2+:args ]     ->  $ids+=1;highlighted($ids,highligh($ids, color_by("blue",name+"("))+args*color_by("blue",",")+highligh($ids,color_by("blue",")")))
        | Apply[ .:name ]                  -> color_by("blue",name)
        | Bind[ trans:expr @name:name ]    -> expr + (name[0]=="_result" ? "" :  color_by("red",":#{name[0]}"))
        | .:x {x.inspect}

  trans2 = Act[ Args[ (Lambda[.:x {x[0]}=>trans:t {$ids+=1;bt=highligh($ids,color_by("yellow","`")); highlighted($ids,"#{bt}#{t}#{bt}")} ]  | .)*:ary]      ] -> color_by("brown",ary*"")
}