derive_builder 0.4.2

Rust macro to automatically implement the builder pattern for arbitrary structs.
Documentation 
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#[macro_use]
extern crate pretty_assertions;
#[macro_use]
extern crate derive_builder;

#[derive(Debug, PartialEq, Default, Builder, Clone)]
#[builder(name="MyBuilder")]
struct Lorem {
    ipsum: &'static str,
    pub dolor: Option<&'static str>,
    pub sit: i32,
    amet: bool,
}

#[test]
#[should_panic(expected="`ipsum` must be initialized")]
fn panic_if_uninitialized() {
    MyBuilder::default().build().unwrap();
}

#[test]
fn builder() {
    let x: Lorem = MyBuilder::default()
        .ipsum("lorem")
        .dolor(Some("dolor"))
        .sit(42)
        .amet(true)
        .build()
        .unwrap();

    assert_eq!(x,
               Lorem {
                   ipsum: "lorem",
                   dolor: Some("dolor"),
                   sit: 42,
                   amet: true,
               });
}