# Objective
Make it so that users can ease between tuples of easeable values.
## Solution
Use `variadics_please`'s `all_tuples_enumerated` macro to generate code
that creates these trait implementations. For two elements, the result
looks like this:
```rust
impl<T0: Ease, T1: Ease> Ease for (T0, T1) {
fn interpolating_curve_unbounded(start: Self, end: Self) -> impl Curve<Self> {
let curve_tuple = (
<T0 as Ease>::interpolating_curve_unbounded(start.0, end.0),
<T1 as Ease>::interpolating_curve_unbounded(start.1, end.1),
);
FunctionCurve::new(Interval::EVERYWHERE, move |t| {
(
curve_tuple.0.sample_unchecked(t),
curve_tuple.1.sample_unchecked(t),
)
})
}
}
```
## Testing
It compiles, and I futzed about with some manual examples, which seem to
work as expected.
---
## Showcase
Easing curves now support easing tuples of values that can themselves be
eased. For example:
```rust
// Easing between two `(Vec3, Quat)` values:
let easing_curve = EasingCurve::new(
(vec3(0.0, 0.0, 0.0), Quat::from_rotation_z(-FRAC_PI_2)),
(vec3(1.0, 1.0, 1.0), Quat::from_rotation_z(FRAC_PI_2)),
EaseFunction::ExponentialInOut
);
```
43d5472fda