Currently, when writing a user-defined function, the parameters can be of six types: bool (scalar variable acting as a Boolean switch), int (scalar variable acting as an integer), scalar (scalar variable), series (data series), list (named list of series) and matrix (named matrix or vector). To make it easier to write a user-defined function and make it more flexible I would appreciate if three other parameter types could be included: * "discrete" (a data series with only discrete values) * "proportion" or "quantile" (a scalar which value is between 0 and 1) * "select" (providing a list of alternatives to select from). As it is now, the first two parameter types, "discrete" and "proportion", could be input to the function as "series" and "scalar", and the user has to let the function check if they are discrete or between 0 and 1. It would be nice if it instead was automatically checked already at the input by the parameter type chosen. For the third parameter type, "select", I imagine writing e.g. function(select rejectionregion["two sided","one sided lower","one sided upper"]) would in the GUI produce a drop-down list for this parameter where one can select one of the alternatives "two sided", "one sided lower" or "one sided upper". This is one of the functions that I currently miss in gretl when writing my own functions and which I would find very useful. Best regards and thanks for a great software Andreas