func declare():any
  fvar(old)
  old = block.select((isset(BLK_FUNC) and isndef(Extern)) ? BLK_FUNC : BLK_HEAD)
  println('string ', s, ' = ', Default, ';')
  block.select(old)
end

func doStrCat:any
  fvar(s1,s2)
  s1 = e_str(Str1)
  s2 = Str2
  if(linked(Result))
    if(not isset(_str_cat_))
      var(_str_cat_)
      declare()
    end
    if(cgt.pt_get_rlink_point(cgt.pt_arr_data(0)) = cgt.pt_arr_var(0))
      println(s, ' += ', s2, ';')
    else
      println(s, ' = ', s1 & s2, ';')
    end
    event(onStrCat, s)
  else
    event(onStrCat, s1 & s2)
  end
end

func Result:any
  if(linked(doStrCat))
    if(not isset(_str_cat_))
      var(_str_cat_)
      declare()
    end
    return(s)
  else
    return(e_str(Str1) & Str2)
  end
end