component_model 0.17.0

//! # 003 - Advanced Assignment
//! 
//! Demonstrates advanced assignment patterns and shows how component model
//! provides type-safe assignment without field name conflicts.

use component_model ::Assign;

#[ derive( Default, Debug, PartialEq, Assign ) ]
struct NetworkConfig
{
  host: String,
  port: i32,
}

#[ derive( Default, Debug, PartialEq, Assign ) ]
struct UserProfile
{
  username: String,
  user_id: i32,
}

fn main()
{
  println!( "=== Advanced Assignment Patterns ===" );
  
  // Network configuration
  let mut net_config = NetworkConfig ::default();
  net_config.assign( "api.example.com" );
  net_config.assign( 443 );
  println!( "Network config: {net_config:?}" );
  
  // User profile with fluent style
  let user_profile = UserProfile ::default()
  .impute( "alice_dev" )
  .impute( 1001 );
  println!( "User profile: {user_profile:?}" );
  
  // Demonstrate type safety - String goes to String field, i32 goes to i32 field
  let mut mixed_config = NetworkConfig ::default();
  mixed_config.assign( 8080 );           // Goes to port (i32)
  mixed_config.assign( "localhost" );    // Goes to host (String)
  
  println!( "Mixed assignment: {mixed_config:?}" );
  
  // Show that order doesn't matter due to type-driven assignment
  let user1 = UserProfile ::default()
  .impute( "bob_user" )      // String -> username
  .impute( 2002 );           // i32 -> user_id
  
  let user2 = UserProfile ::default()
  .impute( 2002 )            // i32 -> user_id  
  .impute( "bob_user" );     // String -> username
  
  // Both should be identical despite different assignment order
  assert_eq!( user1, user2 );
  println!( "Order-independent assignment: {user1:?} == {user2:?}" );
  
  // Verify final state
  assert_eq!( mixed_config.host, "localhost" );
  assert_eq!( mixed_config.port, 8080 );
  assert_eq!( user_profile.username, "alice_dev" );
  assert_eq!( user_profile.user_id, 1001 );
  
  println!( "✅ Advanced assignment patterns complete!" );
}