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use std::convert::TryFrom;
use std::fmt::{self, Debug, Display, Formatter, Write};
use std::iter::FromIterator;
use std::ops::{Add, AddAssign};
use std::rc::Rc;
use super::Value;
use crate::diag::StrResult;
/// Create a new [`Array`] from values.
#[allow(unused_macros)]
macro_rules! array {
($value:expr; $count:expr) => {
$crate::eval::Array::from_vec(vec![$crate::eval::Value::from($value); $count])
};
($($value:expr),* $(,)?) => {
$crate::eval::Array::from_vec(vec![$($crate::eval::Value::from($value)),*])
};
}
/// An array of values with clone-on-write value semantics.
#[derive(Default, Clone, PartialEq)]
pub struct Array {
vec: Rc<Vec<Value>>,
}
impl Array {
/// Create a new, empty array.
pub fn new() -> Self {
Self::default()
}
/// Create a new array from a vector of values.
pub fn from_vec(vec: Vec<Value>) -> Self {
Self { vec: Rc::new(vec) }
}
/// Whether the array is empty.
pub fn is_empty(&self) -> bool {
self.vec.is_empty()
}
/// The length of the array.
pub fn len(&self) -> i64 {
self.vec.len() as i64
}
/// Borrow the value at the given index.
pub fn get(&self, index: i64) -> StrResult<&Value> {
usize::try_from(index)
.ok()
.and_then(|i| self.vec.get(i))
.ok_or_else(|| out_of_bounds(index, self.len()))
}
/// Mutably borrow the value at the given index.
pub fn get_mut(&mut self, index: i64) -> StrResult<&mut Value> {
let len = self.len();
usize::try_from(index)
.ok()
.and_then(move |i| Rc::make_mut(&mut self.vec).get_mut(i))
.ok_or_else(|| out_of_bounds(index, len))
}
/// Push a value to the end of the array.
pub fn push(&mut self, value: Value) {
Rc::make_mut(&mut self.vec).push(value);
}
/// Clear the array.
pub fn clear(&mut self) {
if Rc::strong_count(&mut self.vec) == 1 {
Rc::make_mut(&mut self.vec).clear();
} else {
*self = Self::new();
}
}
/// Iterate over references to the contained values.
pub fn iter(&self) -> std::slice::Iter<Value> {
self.vec.iter()
}
/// Repeat this array `n` times.
pub fn repeat(&self, n: i64) -> StrResult<Self> {
let count = usize::try_from(n)
.ok()
.and_then(|n| self.vec.len().checked_mul(n))
.ok_or_else(|| format!("cannot repeat this array {} times", n))?;
Ok(self.iter().cloned().cycle().take(count).collect())
}
}
/// The out of bounds access error message.
#[cold]
fn out_of_bounds(index: i64, len: i64) -> String {
format!("array index out of bounds (index: {}, len: {})", index, len)
}
impl Debug for Array {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
f.debug_list().entries(self.vec.iter()).finish()
}
}
impl Display for Array {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
f.write_char('(')?;
for (i, value) in self.iter().enumerate() {
Display::fmt(value, f)?;
if i + 1 < self.vec.len() {
f.write_str(", ")?;
}
}
if self.len() == 1 {
f.write_char(',')?;
}
f.write_char(')')
}
}
impl Add for Array {
type Output = Self;
fn add(mut self, rhs: Array) -> Self::Output {
self += rhs;
self
}
}
impl AddAssign for Array {
fn add_assign(&mut self, rhs: Array) {
match Rc::try_unwrap(rhs.vec) {
Ok(vec) => self.extend(vec),
Err(rc) => self.extend(rc.iter().cloned()),
}
}
}
impl FromIterator<Value> for Array {
fn from_iter<T: IntoIterator<Item = Value>>(iter: T) -> Self {
Array { vec: Rc::new(iter.into_iter().collect()) }
}
}
impl Extend<Value> for Array {
fn extend<T: IntoIterator<Item = Value>>(&mut self, iter: T) {
Rc::make_mut(&mut self.vec).extend(iter);
}
}
impl IntoIterator for Array {
type Item = Value;
type IntoIter = std::vec::IntoIter<Value>;
fn into_iter(self) -> Self::IntoIter {
match Rc::try_unwrap(self.vec) {
Ok(vec) => vec.into_iter(),
Err(rc) => (*rc).clone().into_iter(),
}
}
}
impl<'a> IntoIterator for &'a Array {
type Item = &'a Value;
type IntoIter = std::slice::Iter<'a, Value>;
fn into_iter(self) -> Self::IntoIter {
self.iter()
}
}
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