Derive a highly configurable constructor for your struct

Examples

Basic

```rust use fancy_constructor::new;

[derive(new, PartialEq, Eq, Debug)]

struct MyStruct { foo: String, bar: u8, }

let a = MyStruct::new("#[derive(new)]".into(), 55); let b = MyStruct { foo: "#[derive(new)]".into(), bar: 55 }; assert_eq!(a, b); ```

Outputs: ```rust impl MyStruct { pub fn new(foo: String, bar: u8) -> Self { Self { foo, bar } } } ````

Options showcase

```rust

[derive(new, PartialEq, Eq, Debug)]

[new(vis(pub(crate)), name(construct), comment("Foo"), bounds(T: Clone))]

struct MyStruct { #[new(into)] a: T,

#[new(val("Bar".into()))] b: String,

#[new(clone)] c: Arc,

#[new(default)] d: Vec, }

let we = Arc::new(Whatever::default()); let a = MyStruct::::construct("A", &we); let b = MyStruct {a: "A".into(), b: "Bar".into(), c: we, d: vec![]}; assert_eq!(a, b); ```

Outputs:

```rust impl MyStruct { /// Foo pub(crate) fn construct(a: impl Into, c: &Arc) -> Self where T: Clone { Self { a: a.into(), b: "Bar".into(), c: c.clone(), d: Default::default(), } } } ````

Private const fn

```rust

[derive(new, PartialEq, Eq, Debug)]

[new(const_fn, vis())]

struct Foo(u8);

const FOO: Foo = Foo::new(128); assert_eq!(FOO, Foo(128)); ```

Outputs:

```rust impl Foo { const fn new(f1: u8) -> Self { Self(f1) } } ````

Computed values

```rust

[derive(new)]

struct Foo { isbar: bool, #[new(val(if isbar { 100 } else { 5 }))] barness_level: u8, }

asserteq!(Foo::new(true).barnesslevel, 100); asserteq!(Foo::new(false).barnesslevel, 5); ```