some q functions

q-funcs.q

//function return all subset of a list
sset: {[xs] (enlist ()) {x, (y,) each x }/ xs}

//or using the map each right /: 
sset: {[xs] (enlist ()) {x, y ,/: x }/ xs}
//q)sset (1; 2; 3;`a)
()
,1
,2
2 1
,3
3 1
3 2
3 2 1
,`a
(`a;1)
(`a;2)
(`a;2;1)
(`a;3)
(`a;3;1)
(`a;3;2)
(`a;3;2;1)

//fibonacci
fib: {[n] last n {(-1#x),(sum x)}/ (0 1)}