npeg.nim

let dqlParser2 = peg("top_level", stack: ParseStack):
  top_level <- goal * end_marker
  S <- *Space
  end_marker <- "."
  goal <- S * predicate * S * *( separator  * S * goal) * *(unary_op)
  unary_op <- S * "|>" * S * "UN" * S
  separator <- ","
  predicate <- named_predicate | selection_stuff | group
  selection_stuff <- "SEL"
  group <- "GROUP"
  named_predicate <-  >?alias * ?ns_wrapper * >functor * "(" * functorArgs * ")":
    var np = new(NamedPredicate)
    for idx,i in pairs(capture):
      echo "Hi --- ",$i.s
    np.alias = $1
    np.functor_name = $2
    var matching = get_items_matching("namespace", stack)[0]
    let n = Namespace(matching)
    np.ns = n.parts
    stack[].add ("named_predicate",np,)
  alias <- +Alpha * "@"
  ns_part <- +Alpha
  ns_wrapper <- ns:
    var ns = new(Namespace)
    var matching = get_items_matching("ns_part", stack)
    for i in matching.items: 
      ns.parts.add i.data 
    stack[].add (("namespace",ns,))
  ns <- >ns_part * "." * ?ns: 
    var bs = new(BoxedString)
    bs.data = $1
    stack[].add( ("ns_part",bs ))
  functor <- +( {'a'..'z','A'..'Z','0'..'9','_'})
#  functorArgs <- >column * *("," * >column):
#    for idx,i in pairs(capture):
#      if idx!=0:
#        np.args.add(i.s) 
#
  functorArgs <- "A"
  column <- +Alpha