Hi Srini, > Another difference is that the mapcon and mapcan functions must supply > a function that returns a list, while the others can supply a function > that returns an atom?
Not exactly. 'mapcon' and 'mapcan' can return any s-expression. These results are then concatenated just as 'conc' does, and they may well be atoms (most importantly, they can be NIL). This corresponds to : (conc (1) 2 (3 4) 5 (6)) -> (1 3 4 6) while 'maplist' and 'mapcar' build a list from the results, just as 'list' does: : (list (1) 2 (3 4) 5 (6)) -> ((1) 2 (3 4) 5 (6)) ♪♫ Alex -- UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe