Styles in pseudo-code

We have to following procedure, that makes a list of all elements in list L that are smaller than N.

record item v next

define smallerthan in L in N out S
    if L = NIL
	S = NIL
    else
	smallerthan L.next N S
	if L.v < N
	    new item E
	    E.v = L.v
	    E.next = S
	    S = E

We can write this in a function style using the instruction return, that returns the value given by the argument.

record item v next

define smallerthan L N
    if L = NIL
	return NIL
    else
	S = smallerthan L.next N
	if L.v < N
	    new item E
	    E.v = L.v
	    E.next = S
	    S = E
	return S

And put this in a more functional language style.

(record item v next)

(define smallerthan L N
    (if L = NIL
	NIL
	(if L.v < N
	    (new item L.v (smallerthan L.next N))
	    (smallerthan L.next N)
	)
    )
)