feat: Added support for "#[interactive_clap(flatten)]" (#15)

Co-authored-by: FroVolod <frol_off@meta.ua>

examples/struct_with_flatten.rs

@@ -0,0 +1,61 @@
+// This example shows additional functionality of the "interactive-clap" macro for parsing command-line data into a structure using the macro's flatten attributes.
+
+// 1) build an example: cargo build --example struct_with_flatten
+// 2) go to the `examples` folder: cd target/debug/examples
+// 3) run an example: ./struct_with_flatten (without parameters) => entered interactive mode
+//                    ./struct_with_flatten QWERTY 18 => account: CliAccount { social_db_folder: None, account: Some(CliSender { sender_account_id: Some("QWERTY"), age: Some(18) }) }
+// To learn more about the parameters, use "help" flag: ./struct_with_flatten --help
+
+use interactive_clap::{ResultFromCli, ToCliArgs};
+
+#[derive(Debug, Clone, interactive_clap::InteractiveClap)]
+struct Account {
+    /// Change SocialDb prefix
+    #[interactive_clap(long)]
+    #[interactive_clap(skip_interactive_input)]
+    social_db_folder: Option<String>,
+    #[interactive_clap(flatten)]
+    account: Sender,
+}
+
+#[derive(Debug, Clone, interactive_clap::InteractiveClap)]
+pub struct Sender {
+    /// What is the sender account ID?
+    pub sender_account_id: String,
+    /// How old is the sender?
+    pub age: u64,
+}
+
+fn main() -> color_eyre::Result<()> {
+    let mut cli_account = Account::parse();
+    let context = (); // default: input_context = ()
+    loop {
+        let account = <Account as interactive_clap::FromCli>::from_cli(Some(cli_account), context);
+        match account {
+            ResultFromCli::Ok(cli_account) | ResultFromCli::Cancel(Some(cli_account)) => {
+                println!("account: {cli_account:?}");
+                println!(
+                    "Your console command:  {}",
+                    shell_words::join(&cli_account.to_cli_args())
+                );
+                return Ok(());
+            }
+            ResultFromCli::Cancel(None) => {
+                println!("Goodbye!");
+                return Ok(());
+            }
+            ResultFromCli::Back => {
+                cli_account = Default::default();
+            }
+            ResultFromCli::Err(cli_account, err) => {
+                if let Some(cli_account) = cli_account {
+                    println!(
+                        "Your console command:  {}",
+                        shell_words::join(&cli_account.to_cli_args())
+                    );
+                }
+                return Err(err);
+            }
+        }
+    }
+}