Update examples

README.md

@@ -16,7 +16,7 @@ let b = {
 assert!(jet::eq_32(b, 7));
 ```
 
-Take a look at the [example programs](https://github.com/BlockstreamResearch/simfony/tree/master/example_progs).
+Take a look at the [example programs](https://github.com/BlockstreamResearch/simfony/tree/master/examples).
 
 ## MSRV
 

examples/escrow_with_delay.simf

@@ -0,0 +1,63 @@
+/*
+ * ESCROW WITH DELAY
+ *
+ * An escrow agent can approve the movement of coins in cooperation with the
+ * sender or the recipient. The escrow agent cannot steal the coins for himself.
+ * The sender can refund her coins after a timeout.
+ *
+ * https://docs.ivylang.org/bitcoin/language/ExampleContracts.html#escrowwithdelay
+ */
+fn not(bit: bool) -> bool {
+    <u1>::into(jet::complement_1(<bool>::into(bit)))
+}
+
+fn checksig(pk: Pubkey, sig: Signature) {
+    let msg: u256 = jet::sig_all_hash();
+    jet::bip_0340_verify((pk, msg), sig);
+}
+
+fn checksig_add(counter: u8, pk: Pubkey, maybe_sig: Option<Signature>) -> u8 {
+    match maybe_sig {
+        Some(sig: Signature) => {
+            checksig(pk, sig);
+            let (carry, new_counter): (bool, u8) = jet::increment_8(counter);
+            assert!(not(carry));
+            new_counter
+        }
+        None => counter,
+    }
+}
+
+fn check2of3multisig(pks: [Pubkey; 3], maybe_sigs: [Option<Signature>; 3]) {
+    let [pk1, pk2, pk3]: [Pubkey; 3] = pks;
+    let [sig1, sig2, sig3]: [Option<Signature>; 3] = maybe_sigs;
+
+    let counter1: u8 = checksig_add(0, pk1, sig1);
+    let counter2: u8 = checksig_add(counter1, pk2, sig2);
+    let counter3: u8 = checksig_add(counter2, pk3, sig3);
+
+    let threshold: u8 = 2;
+    assert!(jet::eq_8(counter3, threshold));
+}
+
+fn transfer_spend(maybe_sigs: [Option<Signature>; 3]) {
+    let sender_pk: Pubkey = 0x79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798; // 1 * G
+    let recipient_pk: Pubkey = 0xc6047f9441ed7d6d3045406e95c07cd85c778e4b8cef3ca7abac09b95c709ee5; // 2 * G
+    let escrow_pk: Pubkey = 0xf9308a019258c31049344f85f89d5229b531c845836f99b08601f113bce036f9; // 3 * G
+    check2of3multisig([sender_pk, recipient_pk, escrow_pk], maybe_sigs);
+}
+
+fn timeout_spend(sender_sig: Signature) {
+    let sender_pk: Pubkey = 0x79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798; // 1 * G
+    checksig(sender_pk, sender_sig);
+    let timeout: Distance = 1000;
+    jet::check_lock_distance(timeout);
+}
+
+fn main() {
+    let transfer_or_timeout: Either<[Option<Signature>; 3], Signature> = witness("transfer_or_timeout");
+    match transfer_or_timeout {
+        Left(maybe_sigs: [Option<Signature>; 3]) => transfer_spend(maybe_sigs),
+        Right(sender_sig: Signature) => timeout_spend(sender_sig),
+    }
+}

examples/escrow_with_delay.timeout.wit

@@ -0,0 +1,6 @@
+{
+    "transfer_or_timeout": {
+        "value": "Right([0xed, 0xb6, 0x86, 0x50, 0x94, 0x26, 0x0f, 0x85, 0x58, 0x72, 0x82, 0x33, 0xaa, 0xe0, 0x17, 0xdd, 0x09, 0x69, 0xa2, 0xaf, 0xe5, 0xf0, 0x8c, 0x28, 0x2e, 0x1a, 0xb6, 0x59, 0xbf, 0x24, 0x62, 0x68, 0x4c, 0x99, 0xa6, 0x4a, 0x2a, 0x57, 0x24, 0x63, 0x58, 0xa0, 0xd6, 0x32, 0x67, 0x17, 0x78, 0xd0, 0x16, 0xe6, 0xdf, 0x73, 0x81, 0x29, 0x3d, 0xd5, 0xbb, 0x9f, 0x09, 0x99, 0xd3, 0x86, 0x40, 0xd4])",
+        "type": "Either<[Option<[u8; 64]>; 3], [u8; 64]>"
+    }
+}