8fc60af441
One instance remains in net_tcp due to a foreign fn. Lots of instances remain in serialization.rs, but IIRC that is being removed. I had to do unholy things to task-perf-word-count-generic to get it to compile after demoding pipes. I may well have messed up its performance, but it passes.
274 lines
6.3 KiB
Rust
274 lines
6.3 KiB
Rust
//! A standard linked list
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#[forbid(deprecated_mode)];
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use core::cmp::Eq;
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use core::option;
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use option::*;
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use option::{Some, None};
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pub enum List<T> {
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Cons(T, @List<T>),
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Nil,
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}
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/// Cregate a list from a vector
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pub fn from_vec<T: Copy>(v: &[T]) -> @List<T> {
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vec::foldr(v, @Nil::<T>, |h, t| @Cons(*h, t))
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}
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/**
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* Left fold
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*
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* Applies `f` to `u` and the first element in the list, then applies `f` to
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* the result of the previous call and the second element, and so on,
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* returning the accumulated result.
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*
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* # Arguments
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*
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* * ls - The list to fold
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* * z - The initial value
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* * f - The function to apply
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*/
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pub fn foldl<T: Copy, U>(z: T, ls: @List<U>, f: fn((&T), (&U)) -> T) -> T {
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let mut accum: T = z;
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do iter(ls) |elt| { accum = f(&accum, elt);}
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accum
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}
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/**
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* Search for an element that matches a given predicate
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*
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* Apply function `f` to each element of `v`, starting from the first.
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* When function `f` returns true then an option containing the element
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* is returned. If `f` matches no elements then none is returned.
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*/
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pub fn find<T: Copy>(ls: @List<T>, f: fn((&T)) -> bool) -> Option<T> {
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let mut ls = ls;
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loop {
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ls = match *ls {
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Cons(ref hd, tl) => {
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if f(hd) { return Some(*hd); }
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tl
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}
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Nil => return None
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}
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};
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}
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/// Returns true if a list contains an element with the given value
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pub fn has<T: Copy Eq>(ls: @List<T>, elt: T) -> bool {
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for each(ls) |e| {
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if *e == elt { return true; }
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}
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return false;
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}
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/// Returns true if the list is empty
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pub pure fn is_empty<T: Copy>(ls: @List<T>) -> bool {
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match *ls {
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Nil => true,
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_ => false
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}
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}
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/// Returns true if the list is not empty
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pub pure fn is_not_empty<T: Copy>(ls: @List<T>) -> bool {
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return !is_empty(ls);
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}
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/// Returns the length of a list
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pub fn len<T>(ls: @List<T>) -> uint {
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let mut count = 0u;
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iter(ls, |_e| count += 1u);
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count
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}
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/// Returns all but the first element of a list
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pub pure fn tail<T: Copy>(ls: @List<T>) -> @List<T> {
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match *ls {
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Cons(_, tl) => return tl,
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Nil => fail ~"list empty"
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}
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}
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/// Returns the first element of a list
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pub pure fn head<T: Copy>(ls: @List<T>) -> T {
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match *ls {
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Cons(copy hd, _) => hd,
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// makes me sad
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_ => fail ~"head invoked on empty list"
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}
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}
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/// Appends one list to another
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pub pure fn append<T: Copy>(l: @List<T>, m: @List<T>) -> @List<T> {
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match *l {
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Nil => return m,
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Cons(copy x, xs) => {
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let rest = append(xs, m);
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return @Cons(x, rest);
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}
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}
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}
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/*
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/// Push one element into the front of a list, returning a new list
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/// THIS VERSION DOESN'T ACTUALLY WORK
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pure fn push<T: Copy>(ll: &mut @list<T>, vv: T) {
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ll = &mut @cons(vv, *ll)
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}
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*/
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/// Iterate over a list
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pub fn iter<T>(l: @List<T>, f: fn((&T))) {
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let mut cur = l;
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loop {
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cur = match *cur {
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Cons(ref hd, tl) => {
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f(hd);
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tl
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}
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Nil => break
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}
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}
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}
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/// Iterate over a list
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pub fn each<T>(l: @List<T>, f: fn((&T)) -> bool) {
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let mut cur = l;
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loop {
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cur = match *cur {
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Cons(ref hd, tl) => {
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if !f(hd) { return; }
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tl
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}
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Nil => break
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}
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}
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}
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impl<T:Eq> List<T> : Eq {
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pure fn eq(other: &List<T>) -> bool {
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match self {
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Cons(ref e0a, e1a) => {
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match (*other) {
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Cons(ref e0b, e1b) => e0a == e0b && e1a == e1b,
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_ => false
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}
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}
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Nil => {
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match (*other) {
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Nil => true,
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_ => false
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}
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}
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}
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}
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pure fn ne(other: &List<T>) -> bool { !self.eq(other) }
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}
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#[cfg(test)]
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mod tests {
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#[legacy_exports];
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#[test]
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fn test_is_empty() {
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let empty : @list::List<int> = from_vec(~[]);
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let full1 = from_vec(~[1]);
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let full2 = from_vec(~['r', 'u']);
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assert is_empty(empty);
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assert !is_empty(full1);
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assert !is_empty(full2);
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assert !is_not_empty(empty);
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assert is_not_empty(full1);
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assert is_not_empty(full2);
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}
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#[test]
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fn test_from_vec() {
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let l = from_vec(~[0, 1, 2]);
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assert (head(l) == 0);
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let tail_l = tail(l);
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assert (head(tail_l) == 1);
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let tail_tail_l = tail(tail_l);
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assert (head(tail_tail_l) == 2);
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}
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#[test]
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fn test_from_vec_empty() {
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let empty : @list::List<int> = from_vec(~[]);
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assert (empty == @list::Nil::<int>);
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}
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#[test]
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fn test_foldl() {
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fn add(a: &uint, b: &int) -> uint { return *a + (*b as uint); }
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let l = from_vec(~[0, 1, 2, 3, 4]);
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let empty = @list::Nil::<int>;
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assert (list::foldl(0u, l, add) == 10u);
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assert (list::foldl(0u, empty, add) == 0u);
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}
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#[test]
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fn test_foldl2() {
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fn sub(a: &int, b: &int) -> int {
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*a - *b
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}
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let l = from_vec(~[1, 2, 3, 4]);
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assert (list::foldl(0, l, sub) == -10);
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}
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#[test]
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fn test_find_success() {
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fn match_(i: &int) -> bool { return *i == 2; }
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let l = from_vec(~[0, 1, 2]);
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assert (list::find(l, match_) == option::Some(2));
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}
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#[test]
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fn test_find_fail() {
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fn match_(_i: &int) -> bool { return false; }
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let l = from_vec(~[0, 1, 2]);
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let empty = @list::Nil::<int>;
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assert (list::find(l, match_) == option::None::<int>);
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assert (list::find(empty, match_) == option::None::<int>);
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}
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#[test]
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fn test_has() {
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let l = from_vec(~[5, 8, 6]);
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let empty = @list::Nil::<int>;
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assert (list::has(l, 5));
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assert (!list::has(l, 7));
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assert (list::has(l, 8));
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assert (!list::has(empty, 5));
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}
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#[test]
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fn test_len() {
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let l = from_vec(~[0, 1, 2]);
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let empty = @list::Nil::<int>;
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assert (list::len(l) == 3u);
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assert (list::len(empty) == 0u);
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}
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#[test]
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fn test_append() {
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assert from_vec(~[1,2,3,4])
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== list::append(list::from_vec(~[1,2]), list::from_vec(~[3,4]));
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}
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}
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// Local Variables:
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// mode: rust;
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// fill-column: 78;
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// indent-tabs-mode: nil
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// c-basic-offset: 4
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// buffer-file-coding-system: utf-8-unix
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// End:
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