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//! 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. //! 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); //! } //! //! ``` //! //! mod primitive_impls; pub use primitive_impls::*; /// An attribute macro applied to `mod`s. Will generate a Delta and it's `DeltaStruct<_>` implementation. /// /// Applied to a `mod`. Expects the `mod` to have a `struct` with the same name /// and an implementation. Currently at least one field is expected in the `struct` /// definition and at least one method is expected in the implementation. This macro /// will generate an `enum` with the same name as the mod with `Delta` appended, /// and an implementation `impl DeltaStruct<FooDelta> for Foo`. /// /// The delta will have a tuple variant for each method defined for the struct /// converted to camel case, and it's tuple will be of the same type as the /// argument list of it's respective method (without `&mut self`). It will also /// expose delta functions of it's fields. /// /// ## Example: /// /// ``` /// # use deltastruct_proc::deltastruct; /// # use deltastruct::*; /// #[deltastruct] /// mod Foo { /// struct Foo { /// x : i32, /// y : i32 /// } /// /// impl Foo { /// fn swap(&mut self) { /// let tmp = self.x; /// self.x = self.y; /// self.y = tmp; /// } /// /// fn do_stuff(&mut self, n : f64) { /// self.x = (n * (self.x as f64)) as i32; /// } /// } /// } /// ``` /// /// will generate: /// ``` /// # use deltastruct::DeltaStruct; /// # struct Foo; /// # #[allow(non_camel_case_types)] struct i32Delta; /// enum FooDelta { /// Swap(), /// DoStuff(f64), /// X(i32Delta), /// Y(i32Delta), /// } /// /// impl DeltaStruct<FooDelta> for Foo { /// fn apply(&mut self, delta : &FooDelta) { /// /* ... */ /// } /// } /// ``` pub use deltastruct_proc::deltastruct; /// A trait derived for each tagged struct where `T` is it's generated delta. /// /// ``` /// # use deltastruct::*; /// #[deltastruct] /// mod Foo { /// struct Foo { /// bar : bool /// } /// impl Foo { /// fn foobar(&mut self) {} /// } /// } /// ``` /// /// will generate: /// ``` /// # use deltastruct::*; /// # struct Foo; /// # struct FooDelta; /// impl DeltaStruct<FooDelta> for Foo { /// fn apply(&mut self, delta : &FooDelta) { /// /* ... */ /// } /// } /// ``` pub trait DeltaStruct<T> { fn apply(&mut self, delta: &T); } #[cfg(test)] mod tests { use super::*; #[deltastruct] mod Foo { struct Foo { x: i32, y: i32, } impl Foo { pub fn bar(&mut self, a: i64, b: i64) { self.x = ((a * b) as i32) - self.y; } pub fn baz(&mut self, data: u32) { self.x += data as i32; self.y -= data as i32; } } } #[test] fn self_func() { let mut foo = Foo { x: 4, y: 7 }; let dfoo = FooDelta::Baz(5); foo.apply(&dfoo); assert_eq!(foo.x, 9); assert_eq!(foo.y, 2); foo.apply(&dfoo); assert_eq!(foo.x, 14); assert_eq!(foo.y, -3); let dfoo = FooDelta::Bar(3, 4); foo.apply(&dfoo); assert_eq!(foo.x, 15); assert_eq!(foo.y, -3); } #[test] fn field_func() { let mut foo = Foo { x: 3, y: 6 }; let dfoo = FooDelta::X(i32Delta::Set(1)); foo.apply(&dfoo); assert_eq!(foo.x, 1); assert_eq!(foo.y, 6); let dfoo = FooDelta::Y(i32Delta::Set(-20)); foo.apply(&dfoo); assert_eq!(foo.x, 1); assert_eq!(foo.y, -20); } #[test] fn delta_derives() { #[deltastruct(derive(Clone))] mod Testbug { struct Testbug { meh: u8, } impl Testbug { fn bar(&mut self) {} } } let testbugdelta = TestbugDelta::Bar(); testbugdelta.clone(); } }