It seems like you need to supply all four arguments whenever you use TRIMS(). There are no defaults set (I don't know if that is even possible with PROC FCMP). I would like to see defaults, and also a re-arrangement of the order of the parameters so I can just type TRIMS(variablename), which is in my mind more intuitive than typing TRIMS('b',variablename,' ',' '), and also TRIMS(variablename) is less error-prone the way I type.