A procedural macro which creates a "staged" builder for a type.

Staged (also known as telescopic) builders are a style of infallible builders; code will not compile if any required fields are not set. Specifically, the builder advances in order through a sequence of "stage" types, each corresponding to a required field of the struct. The final stage has setters for all optional fields and the final .build() method.

See the documentation for #[staged_builder] for more details.

Examples

use staged_builder::staged_builder;

#[staged_builder]
struct Person {
#[builder(into)]
name: String,
age: u32,
#[builder(default)]
employer: Option<String>,
}

# fn main() {
let person = Person::builder()
.name("John Doe")
.age(25)
.build();
# }