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use super::{Compose, Identity, Invert, Lenticuloid};
#[cfg(not(feature = "nightly"))]
#[inline]
pub fn identity<S, T>() -> Identity<S, T> {
Identity::mk()
}
#[cfg(feature = "nightly")]
#[inline]
pub const fn identity<S, T>() -> Identity<S, T> {
Identity::mk()
}
pub trait ComposeExt<Other>: Lenticuloid + Sized
where Other: Lenticuloid<InitialTarget = Self::InitialSource, FinalTarget = Self::FinalSource>
{
fn compose(self, other: Other) -> Compose<Self, Other>;
}
impl<This, Other> ComposeExt<Other> for This
where This: Lenticuloid,
Other: Lenticuloid<InitialTarget = This::InitialSource, FinalTarget = This::FinalSource>
{
#[inline]
fn compose(self, other: Other) -> Compose<Self, Other> {
Compose::of(self, other)
}
}
#[macro_export]
macro_rules! chain_compose {
() => { $crate::Identity::mk() };
($l:expr) => { $l };
($lf:expr, $($ls:expr),+) => { $crate::Compose::of($lf, chain_compose!($($ls),+)) };
}
pub trait AndThenExt<Other: Lenticuloid>
: Lenticuloid<InitialTarget = Other::InitialSource, FinalTarget = Other::FinalSource> + Sized
where Other: Lenticuloid
{
fn and_then(self, other: Other) -> Compose<Other, Self>;
}
impl<This, Other> AndThenExt<Other> for This
where Other: Lenticuloid,
This: Lenticuloid<InitialTarget = Other::InitialSource, FinalTarget = Other::FinalSource>
{
#[inline]
fn and_then(self, other: Other) -> Compose<Other, Self> {
Compose::of(other, self)
}
}
#[macro_export]
macro_rules! chain_and_then {
() => { $crate::Identity::mk() };
($l:expr) => { $l };
($lf:expr, $($ls:expr),+) => { $crate::Compose::of(chain_and_then!($($ls),+), $lf) };
}
pub trait InvertExt: Lenticuloid + Sized {
fn invert(self) -> Invert<Self>;
}
impl<This: Lenticuloid> InvertExt for This {
#[inline]
fn invert(self) -> Invert<Self> {
Invert::of(self)
}
}
#[macro_export]
macro_rules! field_lens {
($source:ty => $($field_name:tt).*: $target:ty) => {
{
#[derive(Copy,Clone,Debug,Default)]
struct __FieldLens__;
impl $crate::Lenticuloid for __FieldLens__ {
type InitialSource = $source;
type InitialTarget = $target;
type FinalSource = $source;
type FinalTarget = $target;
type AtInitial = Self;
#[inline]
fn at_initial(&self) -> Self::AtInitial {
*self
}
type AtFinal = Self;
#[inline]
fn at_final(&self) -> Self::AtFinal {
*self
}
}
impl $crate::PartialLens for __FieldLens__ {
#[inline]
fn try_get(&self, v: Self::InitialSource) ->
$crate::std::result::Result<Self::InitialTarget, Self::FinalSource>
{
$crate::std::result::Result::Ok(v$(.$field_name)*)
}
#[inline]
fn try_get_inject(&self, mut v: Self::InitialSource) ->
$crate::std::result::Result<(Self::InitialTarget,
$crate::Injector<Self::FinalTarget,
Self::FinalSource>), Self::FinalSource>
{
let x = $crate::std::mem::replace(&mut v$(.$field_name)*, unsafe {
$crate::std::mem::uninitialized()
});
let v_no_drop = $crate::nodrop::NoDrop::new(v);
$crate::std::result::Result::Ok((
x,
$crate::util::once_to_mut(move |y| {
let mut v_final = v_no_drop.into_inner();
$crate::std::mem::forget($crate::std::mem::replace(
&mut v_final$(.$field_name)*,
y
));
v_final
})
))
}
#[inline]
fn set(&self, mut v: Self::InitialSource, x: Self::FinalTarget) ->
Self::FinalSource
{
v$(.$field_name)* = x;
v
}
#[inline]
fn exchange(&self,
mut v: Self::InitialSource,
mut x: Self::FinalTarget) ->
($crate::std::option::Option<Self::InitialTarget>,
Self::FinalSource)
{
$crate::std::mem::swap(&mut v$(.$field_name)*, &mut x);
($crate::std::option::Option::Some(x), v)
}
#[inline]
fn modify<F>(&self, mut v: Self::InitialSource, f: F) -> Self::FinalSource
where F: FnOnce(Self::InitialTarget) -> Self::FinalTarget
{
v$(.$field_name)* = f(v$(.$field_name)*);
v
}
#[inline]
fn modify_with<F, X>(&self, mut v: Self::InitialSource, f: F) ->
(Self::FinalSource, $crate::std::option::Option<X>)
where F: FnOnce(Self::InitialTarget) -> (Self::FinalTarget, X)
{
let (x, aux) = f(v$(.$field_name)*);
v$(.$field_name)* = x;
(v, $crate::std::option::Option::Some(aux))
}
}
impl $crate::Lens for __FieldLens__ {
#[inline]
fn get(&self, v: Self::InitialSource) -> Self::InitialTarget
{
v$(.$field_name)*
}
}
__FieldLens__
}
}
}
#[cfg(test)]
mod test {
use ::PartialLens;
#[test]
fn test_field_lens() {
struct TestInner(String);
struct TestOuter {
pub test_field: TestInner,
}
let l = field_lens!(TestOuter => test_field.0: String);
let v = TestOuter { test_field: TestInner(" hello\n".to_string()) };
let w = l.modify(v, |x| x.trim().to_string());
assert_eq!(w.test_field.0, "hello")
}
}