>det ; det=pop$ ( psh$ ( ev, car, uit, lijst, ln, lst, llst ) , (ln=!arg : (!getcar,?%arg) & !ln+1 | 0) & (lijst=(%,%)) & %:?uit & 0:?som & !!arg:(?%arr,?%xdim,?%ydim) & !xdim:!ydim & %:?lst & !maaklist & prm$(1,!lst) & !som ); maaklist= !xdim+-1: ( <0 | ( ?xdim & (!xdim,!lst):?lst & !maaklist ) ); prm=pop$ ( psh$ ( lsgn, ssgn, len, lst ) , !arg:(?#ssgn,?lst) & !ln:?len & !len: ( ( 1 & (!uit,!lst):?llst & !add ) | ( ?ev & ( ( div$(!ev,2)*2:!ev & -1 ) | 1 ) : ?lsgn & !rot ) ) ); rot= ( !lst : (!getcar,?%lst) & (!uit,!car):?uit & prm$(!ssgn,!lst) & !uit:(?uit,!getcar) & ( !len+-1 : ( 0 | ( ?len & !lsgn*!ssgn:?ssgn & (!lst,!car) : ?lst & !rot ) ) ) ); add=(-1:?n)&!prod*!ssgn+!som:?som; prod= ( ( !llst:(!getcar,?llst) & sel$(!arr,!car+!ydim*(!n+1:?n)) & !!arr*!prod ) | 1 ); iarr=pop$ ( psh$ ( car, arr, val, ind, _mat, dim ) , !arg:(?%_mat,?val) & !!_mat:(?%arr,?%dim) & tbl$(!arr,prodlist$!dim) & -1:?ind & ~!vul & ok ); prodlist=pop$ ( psh$ ( car, tot ) , (tot= ( ( !arg:(!getcar,?arg) & !car*!tot ) | 1 )) & !tot ); vul=!val:(!getcar,?val) & sel$(!arr,!ind+1:?ind) & !car:?!arr & !vul; getcar=(?%car & (!car : ~!lijst)); mat=(a,4,4); iarr$(mat, 1,0 ,0 ,0 , 0,r^2,0 ,0 , 0,0 ,r^2*sin$theta^2*cos$theta^2,r*sin$theta^2*cos$theta, 0,0 ,r*sin$theta^2*cos$theta ,cos$theta^2*-1 );