tautologico

// Polymorphic lists
// Compile with "rustc -o list list.rs"

// more recent versions of the compiler need this for @ pointers
#[feature(managed_boxes)];

// enable macros
#[feature(macro_rules)];

tautologico

let l = list!(5, 4, 4, 3);

tautologico

macro_rules! list(
    ( $e:expr, $($rest:expr),+ ) => ( @Cons($e, list!( $( $rest ),+ )) );
    ( $e:expr ) => ( @Cons($e, @Empty) );
    () => ( @Empty )
)

tautologico

fn length_acc<A>(l: @List<A>, acc: uint) -> uint {
    match *l {
        Empty => acc,
        Cons(_, rest) => length_acc(rest, acc + 1)
    }
}

tautologico

fn length<A>(l: @List<A>) -> uint {
    match *l {
        Empty => 0,
        Cons(_, rest) => 1 + length(rest)
    }
}

fn main() {
    let l = @Cons("3", @Cons("little", @Cons("strings", @Empty)));
    println!("Length of l is {}", length(l));

tautologico

enum List<A> {
    Empty,
    Cons(A, @List<A>)
}

tautologico

// Functional-style integer lists
// Compile with "rustc -o intlist intlist.rs"

// more recent versions of the compiler need this for @ pointers
#[feature(managed_boxes)];

enum IntList {
    Empty,
    Cons(int, @IntList)
}

tautologico

fn main()
{
    let l1 = @Cons(5, @Cons(3, @Cons(7, @Empty)));
    println!("length of l1 is {}", length(l1));
    println!("sum of l1 is {}", sum_list(l1));
}

tautologico

fn sum_list(l: @IntList) -> int {
    match *l {
        Empty => 0,
        Cons(i, rest) => i + sum_list(rest)
    }
}

tautologico

fn length(l: @IntList) -> uint {
    match *l {
        Empty => 0,
        Cons(_, rest) => 1 + length(rest)
    }
}