docs: add KeychainKind based example

Also added a folder to consolidate example utilities.

Author: 110CodingP

Cargo.toml

@@ -74,3 +74,6 @@ name = "esplora_blocking"
 
 [[example]]
 name = "bitcoind_rpc"
+
+[[example]]
+name = "simple_keyring"

examples/example_utils/mod.rs

@@ -0,0 +1,21 @@
+#![allow(dead_code)]
+
+use bitcoin::secp256k1::Secp256k1;
+use miniscript::{Descriptor, DescriptorPublicKey};
+
+pub const DESCRIPTORS: [&str; 8] = [
+    "pkh([21a559b8/44h/1h/0h]tpubDD2jQhEsAU9uU6Qec2M6k5ygyLS96cCa9iwpQrGAS7p6GRW7eVjCiy1WGwTxqCPiACg99A4vUCZWs5w3xgHgTohxYu2z1ZzhLrLaFHG8at1/0/*)#8t439hyk",
+    "pkh([21a559b8/44h/1h/0h]tpubDD2jQhEsAU9uU6Qec2M6k5ygyLS96cCa9iwpQrGAS7p6GRW7eVjCiy1WGwTxqCPiACg99A4vUCZWs5w3xgHgTohxYu2z1ZzhLrLaFHG8at1/1/*)#klsscz5w",
+    "sh(wpkh([21a559b8/49h/1h/0h]tpubDCpBeRAYSsoF8LkbeSa1joNjNPMgTk8jttvydCXTxDwKHJsQab4pr6NeHn11fTKBjHE7NmHrUjEgH3mkQZrQ89qy9tLpZhpMc9w6NvkKkFL/0/*))#5adnu2fe",
+    "sh(wpkh([21a559b8/49h/1h/0h]tpubDCpBeRAYSsoF8LkbeSa1joNjNPMgTk8jttvydCXTxDwKHJsQab4pr6NeHn11fTKBjHE7NmHrUjEgH3mkQZrQ89qy9tLpZhpMc9w6NvkKkFL/1/*))#pur9y4ux",
+    "tr([21a559b8/86h/1h/0h]tpubDCdJ64usD8SEL17thc2K43vG4zHNMdgvnRWNvD3j2bEGCh2ER4KjJN3zhhD54AkBuc5k695JsgkTtdVaARepr2kNxv83zKP5Ra6CsUqoPuu/0/*)#2sd7vzr2",
+    "tr([21a559b8/86h/1h/0h]tpubDCdJ64usD8SEL17thc2K43vG4zHNMdgvnRWNvD3j2bEGCh2ER4KjJN3zhhD54AkBuc5k695JsgkTtdVaARepr2kNxv83zKP5Ra6CsUqoPuu/1/*)#mygl3hnj",
+    "wpkh([21a559b8/84h/1h/0h]tpubDCWfvMa9sCes3z6nxkF7ox5kc6gjddkkJJHTJKfnj96uRGXDWY9WbpNxupEYREV4kHij4JUBYzp9ziM7qhvsUjcisQHaSQgya39nDvuimkF/0/*)#7gmvfd4d",
+    "wpkh([21a559b8/84h/1h/0h]tpubDCWfvMa9sCes3z6nxkF7ox5kc6gjddkkJJHTJKfnj96uRGXDWY9WbpNxupEYREV4kHij4JUBYzp9ziM7qhvsUjcisQHaSQgya39nDvuimkF/1/*)#0u7d5c94"
+];
+
+pub fn get_descriptor(desc_str: &str) -> Descriptor<DescriptorPublicKey> {
+    Descriptor::parse_descriptor(&Secp256k1::new(), desc_str)
+        .unwrap()
+        .0
+}

examples/simple_keyring.rs

@@ -0,0 +1,22 @@
+use bdk_wallet::keyring::KeyRing;
+use bdk_wallet::{KeychainKind, Wallet};
+use bitcoin::Network;
+
+static EXTERNAL_DESCRIPTOR: &str = "tr([5bc5d243/86'/1'/0']tpubDC72NVP1RK5qwy2QdEfWphDsUBAfBu7oiV6jEFooHP8tGQGFVUeFxhgZxuk1j6EQRJ1YsS3th2RyDgReRqCL4zqp4jtuV2z7gbiqDH2iyUS/0/*)";
+static INTERNAL_DESCRIPTOR: &str = "tr([5bc5d243/86'/1'/0']tpubDC72NVP1RK5qwy2QdEfWphDsUBAfBu7oiV6jEFooHP8tGQGFVUeFxhgZxuk1j6EQRJ1YsS3th2RyDgReRqCL4zqp4jtuV2z7gbiqDH2iyUS/1/*)";
+
+// Simple KeyRing, allowing us to build a standard 2-descriptor wallet with receive and change
+// keychains.
+
+fn main() {
+    let mut keyring: KeyRing<KeychainKind> = KeyRing::new(
+        Network::Regtest,
+        KeychainKind::External,
+        EXTERNAL_DESCRIPTOR,
+    );
+    keyring.add_descriptor(KeychainKind::Internal, INTERNAL_DESCRIPTOR, false);
+
+    let mut wallet = Wallet::new(keyring);
+    let address = wallet.reveal_next_address(KeychainKind::External).unwrap();
+    println!("Address at index {}: {}", address.index, address.address)
+}