add example and instructions for pda

examples/program_deployment/methods/guest/src/bin/simple_tail_call.rs

@@ -9,9 +9,8 @@ use nssa_core::program::{
 // It reads a single account, emits it unchanged, and then triggers a tail call
 // to the Hello World program with a fixed greeting.
 
-
 const HELLO_WORLD_PROGRAM_ID_HEX: &str =
-    "7e99d6e2d158f4dea59597011da5d1c2eef17beed6667657f515b387035b935a";
+    "e9dfc5a5d03c9afa732adae6e0edfce4bbb44c7a2afb9f148f4309917eb2de6f";
 
 fn hello_world_program_id() -> ProgramId {
     let hello_world_program_id_bytes: [u8; 32] = hex::decode(HELLO_WORLD_PROGRAM_ID_HEX)

examples/program_deployment/methods/guest/src/bin/tail_call_with_pda.rs

@@ -0,0 +1,76 @@
+use nssa_core::program::{
+    AccountPostState, ChainedCall, PdaSeed, ProgramId, ProgramInput, read_nssa_inputs,
+    write_nssa_outputs_with_chained_call,
+};
+
+// Tail Call with PDA example program.
+//
+// Demonstrates how to chain execution to another program using `ChainedCall`
+// while authorizing program-derived accounts.
+//
+// Expects a single input account whose Account ID is derived from this
+// program’s ID and the fixed PDA seed below (as defined by the
+// `<AccountId as From<(&ProgramId, &PdaSeed)>>` implementation).
+//
+// Emits this account unchanged, then performs a tail call to the
+// Hello-World-with-Authorization program with a fixed greeting. The same
+// account is passed along but marked with `is_authorized = true`.
+
+const HELLO_WORLD_WITH_AUTHORIZATION_PROGRAM_ID_HEX: &str =
+    "1d95c761168a7fa62eb15a3cc74d3f075e6ec98e6c1ac25bd5bcc7e0a9426398";
+const PDA_SEED: PdaSeed = PdaSeed::new([37; 32]);
+
+fn hello_world_program_id() -> ProgramId {
+    let hello_world_program_id_bytes: [u8; 32] =
+        hex::decode(HELLO_WORLD_WITH_AUTHORIZATION_PROGRAM_ID_HEX)
+            .unwrap()
+            .try_into()
+            .unwrap();
+    bytemuck::cast(hello_world_program_id_bytes)
+}
+
+fn main() {
+    // Read inputs
+    let (
+        ProgramInput {
+            pre_states,
+            instruction: _,
+        },
+        instruction_data,
+    ) = read_nssa_inputs::<()>();
+
+    // Unpack the input account pre state
+    let [pre_state] = pre_states
+        .clone()
+        .try_into()
+        .unwrap_or_else(|_| panic!("Input pre states should consist of a single account"));
+
+    // Create the (unchanged) post state
+    let post_state = AccountPostState::new(pre_state.account.clone());
+
+    // Create the chained call
+    let chained_call_greeting: Vec<u8> =
+        b"Hello from tail call with Program Derived Account ID".to_vec();
+    let chained_call_instruction_data = risc0_zkvm::serde::to_vec(&chained_call_greeting).unwrap();
+
+    // Flip the `is_authorized` flag to true
+    let pre_state_for_chained_call = {
+        let mut this = pre_state.clone();
+        this.is_authorized = true;
+        this
+    };
+    let chained_call = ChainedCall {
+        program_id: hello_world_program_id(),
+        instruction_data: chained_call_instruction_data,
+        pre_states: vec![pre_state_for_chained_call],
+        pda_seeds: vec![PDA_SEED],
+    };
+
+    // Write the outputs
+    write_nssa_outputs_with_chained_call(
+        instruction_data,
+        vec![pre_state],
+        vec![post_state],
+        vec![chained_call],
+    );
+}