Shortest implementation of a linked list, stack and queue

Haskell, 81 69 characters

data L a=N|a:~L a
N~:z=z:~N
(a:~b)~:z=a:~(b~:z)
r N=N
r(a:~z)=r z~:a

This code makes use of no preexisting functions at all. The push operation is :~, the enqueue operation is ~:. Both pop and dequeue are via pattern match against :~. The extra operation r is reverse.

Stacks:

ex1 =
    let stack0 = N                      -- empty stack
        stack1 = 'a' :~ stack0          -- push 'a'
        stack2 = 'b' :~ stack1          -- push 'b'
        first :~ stack3 = stack2        -- pop
        second :~ stack4 = stack3       -- pop
    in mapM_ print [first, second]

—

λ: ex1
'b'
'a'

Queues:

ex2 =
    let queue0 = N                      -- empty queue
        queue1 = queue0 ~: 'x'          -- enq 'x'
        queue2 = queue1 ~: 'y'          -- enq 'y'
        queue3 = queue2 ~: 'z'          -- enq 'z'
        next0 :~ queue4 = queue3        -- deq
        next1 :~ queue5 = queue4        -- deq
        next2 :~ queue6 = queue5        -- deq
    in mapM_ print [next0, next1, next2]

—

λ: ex2
'x'
'y'
'z'

List reverse operation:

ex3 =
    let list = "alpha" :~ ("beta" :~ ("gamma" :~ N)) -- a list
        tsil = r list                   -- reverse the list
        native N = []                   -- convert to native list
        native (a:~z) = a : native z    -- for easy printing
    in mapM_ (print . native) [list, tsil]

—

λ: ex3
["alpha","beta","gamma"]
["gamma","beta","alpha"]