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stabilize core::option 

Per API meeting

  https://github.com/rust-lang/meeting-minutes/blob/master/Meeting-API-review-2014-08-13.md

Most of the module is marked as stable or unstable; most of the unstable
items are awaiting resolution of conventions issues.

However, a few methods have been deprecated, either due to lack of use
or redundancy:

* `take_unwrap`, `get_ref` and `get_mut_ref` (redundant, and we prefer
  for this functionality to go through an explicit .unwrap)
* `filtered` and `while`
* `mutate` and `mutate_or_set`
* `collect`: this functionality is being moved to a new `FromIterator`
  impl.

Due to deprecations, this is a:

[breaking-change]
This commit is contained in:
Aaron Turon 2014-08-18 17:42:11 -07:00
parent 0d3bd7720c
commit 3a52ef4613
1 changed files with 102 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

143
src/libcore/option.rs
View File

@ -141,6 +141,8 @@
//! }
//! ```
#![stable]
use cmp::{PartialEq, Eq, Ord};
use default::Default;
use slice::Slice;
@ -155,6 +157,7 @@ use slice;
/// The `Option` type.
#[deriving(Clone, PartialEq, PartialOrd, Eq, Ord, Show)]
#[stable]
pub enum Option<T> {
/// No value
None,
@ -173,6 +176,7 @@ impl<T> Option<T> {
/// Returns `true` if the option is a `Some` value
#[inline]
#[stable]
pub fn is_some(&self) -> bool {
match *self {
Some(_) => true,
@ -182,6 +186,7 @@ impl<T> Option<T> {
/// Returns `true` if the option is a `None` value
#[inline]
#[stable]
pub fn is_none(&self) -> bool {
!self.is_some()
}
@ -207,18 +212,21 @@ impl<T> Option<T> {
/// println!("still can print num_as_str: {}", num_as_str);
/// ```
#[inline]
#[stable]
pub fn as_ref<'r>(&'r self) -> Option<&'r T> {
match *self { Some(ref x) => Some(x), None => None }
}
/// Convert from `Option<T>` to `Option<&mut T>`
#[inline]
#[unstable = "waiting for mut conventions"]
pub fn as_mut<'r>(&'r mut self) -> Option<&'r mut T> {
match *self { Some(ref mut x) => Some(x), None => None }
}
/// Convert from `Option<T>` to `&mut [T]` (without copying)
#[inline]
#[unstable = "waiting for mut conventions"]
pub fn as_mut_slice<'r>(&'r mut self) -> &'r mut [T] {
match *self {
Some(ref mut x) => {
@ -243,6 +251,7 @@ impl<T> Option<T> {
/// Fails if the value is a `None` with a custom failure message provided by
/// `msg`.
#[inline]
#[unstable = "waiting for conventions"]
pub fn expect(self, msg: &str) -> T {
match self {
Some(val) => val,
@ -262,6 +271,7 @@ impl<T> Option<T> {
/// Instead, prefer to use pattern matching and handle the `None`
/// case explicitly.
#[inline]
#[unstable = "waiting for conventions"]
pub fn unwrap(self) -> T {
match self {
Some(val) => val,
@ -271,6 +281,7 @@ impl<T> Option<T> {
/// Returns the contained value or a default.
#[inline]
#[unstable = "waiting for conventions"]
pub fn unwrap_or(self, def: T) -> T {
match self {
Some(x) => x,
@ -280,6 +291,7 @@ impl<T> Option<T> {
/// Returns the contained value or computes it from a closure.
#[inline]
#[unstable = "waiting for conventions"]
pub fn unwrap_or_else(self, f: || -> T) -> T {
match self {
Some(x) => x,
@ -303,18 +315,30 @@ impl<T> Option<T> {
/// let num_as_int: Option<uint> = num_as_str.map(|n| n.len());
/// ```
#[inline]
#[unstable = "waiting for unboxed closures"]
pub fn map<U>(self, f: |T| -> U) -> Option<U> {
match self { Some(x) => Some(f(x)), None => None }
}
/// Applies a function to the contained value or returns a default.
#[inline]
#[unstable = "waiting for unboxed closures"]
pub fn map_or<U>(self, def: U, f: |T| -> U) -> U {
match self { None => def, Some(t) => f(t) }
}
/// Applies a function to the contained value or computes a default.
#[inline]
#[unstable = "waiting for unboxed closures"]
pub fn map_or_else<U>(self, def: || -> U, f: |T| -> U) -> U {
match self { None => def(), Some(t) => f(t) }
}
/// Deprecated.
///
/// Applies a function to the contained value or does nothing.
/// Returns true if the contained value was mutated.
#[deprecated = "removed due to lack of use"]
pub fn mutate(&mut self, f: |T| -> T) -> bool {
if self.is_some() {
*self = Some(f(self.take_unwrap()));
@ -322,8 +346,11 @@ impl<T> Option<T> {
} else { false }
}
/// Deprecated.
///
/// Applies a function to the contained value or sets it to a default.
/// Returns true if the contained value was mutated, or false if set to the default.
#[deprecated = "removed due to lack of use"]
pub fn mutate_or_set(&mut self, def: T, f: |T| -> T) -> bool {
if self.is_some() {
*self = Some(f(self.take_unwrap()));
@ -340,18 +367,21 @@ impl<T> Option<T> {
/// Returns an iterator over the possibly contained value.
#[inline]
#[unstable = "waiting for iterator conventions"]
pub fn iter<'r>(&'r self) -> Item<&'r T> {
Item{opt: self.as_ref()}
}
/// Returns a mutable iterator over the possibly contained value.
#[inline]
#[unstable = "waiting for iterator conventions"]
pub fn mut_iter<'r>(&'r mut self) -> Item<&'r mut T> {
Item{opt: self.as_mut()}
}
/// Returns a consuming iterator over the possibly contained value.
#[inline]
#[unstable = "waiting for iterator conventions"]
pub fn move_iter(self) -> Item<T> {
Item{opt: self}
}
@ -362,6 +392,7 @@ impl<T> Option<T> {
/// Returns `None` if the option is `None`, otherwise returns `optb`.
#[inline]
#[stable]
pub fn and<U>(self, optb: Option<U>) -> Option<U> {
match self {
Some(_) => optb,
@ -372,6 +403,7 @@ impl<T> Option<T> {
/// Returns `None` if the option is `None`, otherwise calls `f` with the
/// wrapped value and returns the result.
#[inline]
#[unstable = "waiting for unboxed closures"]
pub fn and_then<U>(self, f: |T| -> Option<U>) -> Option<U> {
match self {
Some(x) => f(x),
@ -381,6 +413,7 @@ impl<T> Option<T> {
/// Returns the option if it contains a value, otherwise returns `optb`.
#[inline]
#[stable]
pub fn or(self, optb: Option<T>) -> Option<T> {
match self {
Some(_) => self,
@ -391,6 +424,7 @@ impl<T> Option<T> {
/// Returns the option if it contains a value, otherwise calls `f` and
/// returns the result.
#[inline]
#[unstable = "waiting for unboxed closures"]
pub fn or_else(self, f: || -> Option<T>) -> Option<T> {
match self {
Some(_) => self,
@ -404,12 +438,16 @@ impl<T> Option<T> {
/// Takes the value out of the option, leaving a `None` in its place.
#[inline]
#[stable]
pub fn take(&mut self) -> Option<T> {
mem::replace(self, None)
}
/// Deprecated.
///
/// Filters an optional value using a given function.
#[inline(always)]
#[deprecated = "removed due to lack of use"]
pub fn filtered(self, f: |t: &T| -> bool) -> Option<T> {
match self {
Some(x) => if f(&x) { Some(x) } else { None },
@ -417,8 +455,11 @@ impl<T> Option<T> {
}
}
/// Deprecated.
///
/// Applies a function zero or more times until the result is `None`.
#[inline]
#[deprecated = "removed due to lack of use"]
pub fn while_some(self, f: |v: T| -> Option<T>) {
let mut opt = self;
loop {
@ -433,6 +474,8 @@ impl<T> Option<T> {
// Common special cases
/////////////////////////////////////////////////////////////////////////
/// Deprecated: use `take().unwrap()` instead.
///
/// The option dance. Moves a value out of an option type and returns it,
/// replacing the original with `None`.
///
@ -440,6 +483,7 @@ impl<T> Option<T> {
///
/// Fails if the value equals `None`.
#[inline]
#[deprecated = "use take().unwrap() instead"]
pub fn take_unwrap(&mut self) -> T {
match self.take() {
Some(x) => x,
@ -447,6 +491,8 @@ impl<T> Option<T> {
}
}
/// Deprecated: use `as_ref().unwrap()` instead.
///
/// Gets an immutable reference to the value inside an option.
///
/// # Failure
@ -460,6 +506,7 @@ impl<T> Option<T> {
/// Instead, prefer to use pattern matching and handle the `None`
/// case explicitly.
#[inline]
#[deprecated = "use .as_ref().unwrap() instead"]
pub fn get_ref<'a>(&'a self) -> &'a T {
match *self {
Some(ref x) => x,
@ -467,6 +514,8 @@ impl<T> Option<T> {
}
}
/// Deprecated: use `as_mut().unwrap()` instead.
///
/// Gets a mutable reference to the value inside an option.
///
/// # Failure
@ -480,6 +529,7 @@ impl<T> Option<T> {
/// Instead, prefer to use pattern matching and handle the `None`
/// case explicitly.
#[inline]
#[deprecated = "use .as_mut().unwrap() instead"]
pub fn get_mut_ref<'a>(&'a mut self) -> &'a mut T {
match *self {
Some(ref mut x) => x,
@ -512,6 +562,7 @@ impl<T: Default> Option<T> {
/// assert_eq!(0i, bad_year);
/// ```
#[inline]
#[unstable = "waiting for conventions"]
pub fn unwrap_or_default(self) -> T {
match self {
Some(x) => x,
@ -527,6 +578,7 @@ impl<T: Default> Option<T> {
impl<T> Slice<T> for Option<T> {
/// Convert from `Option<T>` to `&[T]` (without copying)
#[inline]
#[stable]
fn as_slice<'a>(&'a self) -> &'a [T] {
match *self {
Some(ref x) => slice::ref_slice(x),
@ -552,6 +604,7 @@ impl<T> Default for Option<T> {
/// The `Item` iterator is returned by the `iter`, `mut_iter` and `move_iter`
/// methods on `Option`.
#[deriving(Clone)]
#[unstable = "waiting for iterator conventions"]
pub struct Item<A> {
opt: Option<A>
}
@ -584,54 +637,62 @@ impl<A> ExactSize<A> for Item<A> {}
// Free functions
/////////////////////////////////////////////////////////////////////////////
/// Takes each element in the `Iterator`: if it is `None`, no further
/// elements are taken, and the `None` is returned. Should no `None` occur, a
/// vector containing the values of each `Option` is returned.
///
/// Here is an example which increments every integer in a vector,
/// checking for overflow:
///
/// ```rust
/// use std::option;
/// use std::uint;
///
/// let v = vec!(1u, 2u);
/// let res: Option<Vec<uint>> = option::collect(v.iter().map(|x: &uint|
/// if *x == uint::MAX { None }
/// else { Some(x + 1) }
/// ));
/// assert!(res == Some(vec!(2u, 3u)));
/// ```
/// Deprecated: use `Iterator::collect` instead.
#[inline]
pub fn collect<T, Iter: Iterator<Option<T>>, V: FromIterator<T>>(iter: Iter) -> Option<V> {
// FIXME(#11084): This could be replaced with Iterator::scan when this
// performance bug is closed.
#[deprecated = "use Iterator::collect instead"]
pub fn collect<T, Iter: Iterator<Option<T>>, V: FromIterator<T>>(mut iter: Iter) -> Option<V> {
iter.collect()
}
struct Adapter<Iter> {
iter: Iter,
found_none: bool,
}
impl<A, V: FromIterator<A>> FromIterator<Option<A>> for Option<V> {
/// Takes each element in the `Iterator`: if it is `None`, no further
/// elements are taken, and the `None` is returned. Should no `None` occur, a
/// container with the values of each `Option` is returned.
///
/// Here is an example which increments every integer in a vector,
/// checking for overflow:
///
/// ```rust
/// use std::uint;
///
/// let v = vec!(1u, 2u);
/// let res: Option<Vec<uint>> = v.iter().map(|x: &uint|
/// if *x == uint::MAX { None }
/// else { Some(x + 1) }
/// ).collect();
/// assert!(res == Some(vec!(2u, 3u)));
/// ```
#[inline]
fn from_iter<I: Iterator<Option<A>>>(iter: I) -> Option<V> {
// FIXME(#11084): This could be replaced with Iterator::scan when this
// performance bug is closed.
impl<T, Iter: Iterator<Option<T>>> Iterator<T> for Adapter<Iter> {
#[inline]
fn next(&mut self) -> Option<T> {
match self.iter.next() {
Some(Some(value)) => Some(value),
Some(None) => {
self.found_none = true;
None
struct Adapter<Iter> {
iter: Iter,
found_none: bool,
}
impl<T, Iter: Iterator<Option<T>>> Iterator<T> for Adapter<Iter> {
#[inline]
fn next(&mut self) -> Option<T> {
match self.iter.next() {
Some(Some(value)) => Some(value),
Some(None) => {
self.found_none = true;
None
}
None => None,
}
None => None,
}
}
}
let mut adapter = Adapter { iter: iter, found_none: false };
let v: V = FromIterator::from_iter(adapter.by_ref());
let mut adapter = Adapter { iter: iter, found_none: false };
let v: V = FromIterator::from_iter(adapter.by_ref());
if adapter.found_none {
None
} else {
Some(v)
if adapter.found_none {
None
} else {
Some(v)
}
}
}