add docs to transfer multiple program

risc0-selective-privacy-poc/program_methods/guest/src/bin/pinata.rs

@@ -10,7 +10,8 @@ const PINATA_PRIZE: u128 = 100;
 /// A Piñata program
 /// To be used both in public and privacy contexts.
 fn main() {
-    // Read input accounts. It is expected to receive only two accounts: [pinata_account, winner_account]
+    // Read input accounts.
+    // It is expected to receive only two accounts: [pinata_account, winner_account]
     let mut input_accounts: Vec<Account> = env::read();
 
     // Read claimed preimage
@@ -18,8 +19,7 @@ fn main() {
 
     // Unpack accounts.
     assert_eq!(input_accounts.len(), 2);
-    let [winner_account] = input_accounts.split_off(1).try_into().unwrap();
-    let [pinata_account] = input_accounts.try_into().unwrap();
+    let [pinata_account, winner_account] = input_accounts.try_into().unwrap();
 
     // Check that the given `pinata_account` is correct
     assert_eq!(pinata_account.address, PINATA_ACCOUNT_ADDR);

risc0-selective-privacy-poc/program_methods/guest/src/bin/transfer.rs

@@ -4,6 +4,8 @@ use risc0_zkvm::guest::env;
 /// A transfer of balance program.
 /// To be used both in public and private contexts.
 fn main() {
+    // Read input accounts.
+    // It is expected to receive only two accounts: [sender_account, receiver_account]
     let input_accounts: Vec<Account> = env::read();
     let balance_to_move: u128 = env::read();
 

risc0-selective-privacy-poc/program_methods/guest/src/bin/transfer_multiple.rs

@@ -1,26 +1,35 @@
 use core::account::Account;
 use risc0_zkvm::guest::env;
 
-/// A transfer of balance program with multiple recipients.
+/// A transfer of balance program with one sender and multiple recipients.
 /// To be used both in public and private contexts.
 fn main() {
+    // Read input accounts.
+    // First account is the sender.
     let mut input_accounts: Vec<Account> = env::read();
+
+    // Read the balances to be send to each recipient
     let target_balances: Vec<u128> = env::read();
 
+    // Check that there is at least one recipient
     assert!(input_accounts.len() > 1);
+
+    // Check that there's one target balance for each recipient.
     assert_eq!(target_balances.len() + 1, input_accounts.len());
 
-    let receivers = input_accounts.split_off(1);
+    // Unpack sender and recipients
+    let recipients = input_accounts.split_off(1);
     let sender = input_accounts.pop().unwrap();
-    let total_balance_to_move = target_balances.iter().sum();
 
-    // Check sender has enough balance
+    // Check that the sender has enough balance to pay to all recipients
+    let total_balance_to_move = target_balances.iter().sum();
     assert!(sender.balance >= total_balance_to_move);
 
     // Create accounts post states, with updated balances
     let mut sender_post = sender.clone();
-    let mut receivers_post = receivers.clone();
+    let mut receivers_post = recipients.clone();
 
+    // Transfer balances
     sender_post.balance -= total_balance_to_move;
     for (receiver, balance_for_receiver) in receivers_post.iter_mut().zip(target_balances) {
         receiver.balance += balance_for_receiver;
@@ -29,7 +38,7 @@ fn main() {
     // Flatten pre and post states for output
     let inputs_outputs: Vec<Account> = vec![sender]
         .into_iter()
-        .chain(receivers)
+        .chain(recipients)
         .chain(vec![sender_post])
         .chain(receivers_post)
         .collect();