Create custom serializable changes to apply later
Deltastruct is an attribute macro that generates definitions for serializable changes (called deltas) over structs recursively.
For techinical reasons, the attribute macro must be applied to a mod
definition containing a struct with the same name and an impl for
it's change definitions. Function names are converted to camel case to
appease the compiler.
The generated deltas are always the type name followed by Delta. ie: Foo -> FooDelta, i32 -> i32Delta.
# use deltastruct::*;
#[deltastruct]
mod Vector3 {
#[derive(Clone, Copy)]
pub struct Vector3 {
pub x : f64,
pub y : f64,
pub z : f64,
}
impl Vector3 {
fn set(&mut self, other : Vector3) {
// Copy the given vec's components into our own.
// Alternatively Vector3 can be Copy instead of passing a reference to
// a Vector3
self.x = other.x;
self.y = other.y;
self.z = other.z;
}
fn multiply_scalar(&mut self, n : f64) {
// Multiply each component by the given value
self.x *= n;
self.y *= n;
self.z *= n;
}
fn normalize(&mut self) {
// divide each component by the vector's magnitude
let magnitude = (
self.x.powf(2f64)
+ self.y.powf(2f64)
+ self.z.powf(2f64)
).sqrt();
self.x /= magnitude;
self.y /= magnitude;
self.z /= magnitude;
}
}
}
fn main() {
let mut v = Vector3 {
x: 3f64,
y: 6f64,
z: 6f64
};
let v_delta = Vector3Delta::MultiplyScalar(4f64);
v.apply(&v_delta);
v.apply(&v_delta);
assert_eq!(v.x, 48f64);
let v_delta = Vector3Delta::Normalize();
v.apply(&v_delta);
assert_eq!(v.z, 2f64/3f64);
let v_delta = Vector3Delta::X(f64Delta::Set(8f64));
v.apply(&v_delta);
assert_eq!(v.x, 8f64);
}