char* TRI_GetNameParseAql (TRI_aql_context_t* const context) {
  char buffer[16];
  int n;

  assert(context);

  n = snprintf(buffer, sizeof(buffer) - 1, "_%d", (int) ++context->_variableIndex);

  // register the string and return the copy of it
  return TRI_RegisterStringAql(context, buffer, (size_t) n, false);
}
static TRI_aql_node_t* InjectParameter (TRI_aql_statement_walker_t* const walker,
                                        TRI_aql_node_t* node) {
  TRI_aql_bind_parameter_t* bind;
  TRI_associative_pointer_t* bindValues;
  TRI_aql_context_t* context;
  char* name;

  if (node == NULL || 
      node->_type != TRI_AQL_NODE_PARAMETER) {
    return node;
  }

  // we found a parameter node
  context = (TRI_aql_context_t*) walker->_data;
  assert(context);

  bindValues = (TRI_associative_pointer_t*) &context->_parameters._values;
  assert(bindValues);

  name = TRI_AQL_NODE_STRING(node);
  assert(name);

  bind = (TRI_aql_bind_parameter_t*) TRI_LookupByKeyAssociativePointer(bindValues, name);

  if (bind) {
    if (*name == '@') {
      // a collection name bind parameter
      if (TRI_IsStringJson(bind->_value)) {
        char* collectionName = TRI_RegisterStringAql(context,
                                                     bind->_value->_value._string.data,
                                                     bind->_value->_value._string.length - 1,
                                                     false);

        node = TRI_CreateNodeCollectionAql(context, collectionName);
      }
      else {
        TRI_SetErrorContextAql(context, TRI_ERROR_QUERY_BIND_PARAMETER_TYPE, name);
        node = NULL;
      }
    }
    else {
      node = TRI_JsonNodeAql(context, bind->_value);
    }

    if (node == NULL) {
      TRI_SetErrorContextAql(context, TRI_ERROR_QUERY_BIND_PARAMETERS_INVALID, NULL);
    }
  }

  return node;
}
TRI_aql_node_t* TRI_JsonNodeAql (TRI_aql_context_t* const context,
                                 const TRI_json_t* const json) {
  TRI_aql_node_t* node = NULL;
  char* value;

  switch (json->_type) {
    case TRI_JSON_UNUSED:
      break;

    case TRI_JSON_NULL:
      node = TRI_CreateNodeValueNullAql(context);
      break;

    case TRI_JSON_BOOLEAN:
      node = TRI_CreateNodeValueBoolAql(context, json->_value._boolean);
      break;

    case TRI_JSON_NUMBER:
      node = TRI_CreateNodeValueDoubleAql(context, json->_value._number);
      break;

    case TRI_JSON_STRING:
      value = TRI_RegisterStringAql(context, json->_value._string.data, strlen(json->_value._string.data), true);
      node = TRI_CreateNodeValueStringAql(context, value);
      break;

    case TRI_JSON_LIST: {
      size_t i;
      size_t n;

      node = TRI_CreateNodeListAql(context);
      n = json->_value._objects._length;

      for (i = 0; i < n; ++i) {
        TRI_json_t* subJson;
        TRI_aql_node_t* member;

        subJson = (TRI_json_t*) TRI_AtVector(&json->_value._objects, i);
        assert(subJson);

        member = TRI_JsonNodeAql(context, subJson);
        if (member) {
          TRI_PushBackVectorPointer(&node->_members, (void*) member);
        }
        else {
          TRI_SetErrorContextAql(context, TRI_ERROR_OUT_OF_MEMORY, NULL);
          return NULL;
        }
      }
      break;
    }
    case TRI_JSON_ARRAY: {
      size_t i;
      size_t n;

      node = TRI_CreateNodeArrayAql(context);
      n = json->_value._objects._length;

      for (i = 0; i < n; i += 2) {
        TRI_json_t* nameJson;
        TRI_json_t* valueJson;
        TRI_aql_node_t* member;
        TRI_aql_node_t* valueNode;
        char* name;

        // json_t containing the array element name
        nameJson = (TRI_json_t*) TRI_AtVector(&json->_value._objects, i);
        assert(nameJson);
        assert(nameJson->_value._string.data);
        name = TRI_RegisterStringAql(context, nameJson->_value._string.data, strlen(nameJson->_value._string.data), false);
        if (! name) {
          TRI_SetErrorContextAql(context, TRI_ERROR_OUT_OF_MEMORY, NULL);
          return NULL;
        }

        // json_t containing the array element value
        valueJson = (TRI_json_t*) TRI_AtVector(&json->_value._objects, i + 1);
        assert(valueJson);

        valueNode = TRI_JsonNodeAql(context, valueJson);
        if (! valueNode) {
          TRI_SetErrorContextAql(context, TRI_ERROR_OUT_OF_MEMORY, NULL);
          return NULL;
        }

        member = TRI_CreateNodeArrayElementAql(context, name, valueNode);
        if (member) {
          TRI_PushBackVectorPointer(&node->_members, (void*) member);
        }
        else {
          TRI_SetErrorContextAql(context, TRI_ERROR_OUT_OF_MEMORY, NULL);
          return NULL;
        }
      }
      break;
    }
  }

  if (! node) {
    TRI_SetErrorContextAql(context, TRI_ERROR_OUT_OF_MEMORY, NULL);
  }

  return node;
}