On 28 Mar 2013, at 14:36, Pierre Fenoll wrote: > As per the doc, the spec of lists:append/2 is ([term()], [term()]) -> [term()]. > > However, a = lists:append([], a). If the spec was ([term()], term()) then maybe ;-) Also, the documentation (and implementation as well) clearly states it's equivalent to A ++ B. A.