In a mixing bowl, cream butter, shortening, and sugars until fluffy. Add eggs and vanilla; beat well. Combine flour, baking powder, baking soda and aslat; gradually add to creamed mixture. Fold in oats, coconut and nuts. Drop by tablespoonfuls onto greased baking sheets. Bake at 190ºC or 10-11 minutes or until golden brown. Cool 2-3 minutes before removing to a wire rack. Yield about 5 dozen.