former 2.43.0

A flexible implementation of the Builder pattern supporting nested builders and collection-specific subformers. Simplify the construction of complex objects.
Documentation 
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//! Example demonstrating custom default values for struct fields using Former.

#![allow(missing_docs)]

// ## Example : Custom Defaults
//
// Former allows the specification of custom default values for fields through the `former( default )` attribute.
//
// This feature not only provides a way to set initial values for struct fields without relying on the `Default` trait but also adds flexibility in handling cases where a field's type does not implement `Default`, or a non-standard default value is desired.
// The example showcases the `Former` crate's ability to initialize struct fields with custom default values:
// - The `number` field is initialized to `5`.
// - The `greeting` field defaults to a greeting message, "Hello, Former!".
// - The `numbers` field starts with a vector containing the integers `10`, `20`, and `30`.
//
// This approach significantly simplifies struct construction, particularly for complex types or where defaults beyond the `Default` trait's capability are required. By utilizing the `default` attribute, developers can ensure their structs are initialized safely and predictably, enhancing code clarity and maintainability.
//

#[cfg(any(not(feature = "derive_former"), not(feature = "enabled")))]
fn main() {}

#[cfg(all(feature = "derive_former", feature = "enabled"))]
fn main() {
  #[ cfg( feature = "enabled" ) ]
  use former::Former;

  /// Structure with default attributes.
  #[ derive( Debug, PartialEq, Former ) ]
  pub struct ExampleStruct {
    #[ former( default = 5 ) ]
    number: i32,
    #[ former( default = "Hello, Former!".to_string() ) ]
    greeting: String,
    #[ former( default = vec![ 10, 20, 30 ] ) ]
    numbers: Vec<i32>,
  }

  //

  let instance = ExampleStruct::former().form();
  let expected = ExampleStruct {
    number: 5,
    greeting: "Hello, Former!".to_string(),
    numbers: vec![10, 20, 30],
  };
  assert_eq!(instance, expected);
  dbg!(&instance);
  // > &instance = ExampleStruct {
  // >    number: 5,
  // >    greeting: "Hello, Former!",
  // >    numbers: [
  // >        10,
  // >        20,
  // >        30,
  // >    ],
  // > }
}