Add some more error stuff.

wgps/src/commitment_scheme/execute_prelude.rs

@@ -14,8 +14,11 @@ use super::{
     send_prelude::send_prelude,
 };
 
+/// An error which only occurs during the initial phase of a WGPS session.
 pub enum ExecutePreludeError<E> {
+    /// There was a problem receiving their prelude.
     ReceiveError(ReceivePreludeError<E>),
+    /// There was a problem sending our prelude.
     SendError(E),
 }
 
@@ -31,6 +34,17 @@ impl<E> From<E> for ExecutePreludeError<E> {
     }
 }
 
+impl<E: core::fmt::Display> core::fmt::Display for ExecutePreludeError<E> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            ExecutePreludeError::ReceiveError(receive_prelude_error) => {
+                write!(f, "{}", receive_prelude_error)
+            }
+            ExecutePreludeError::SendError(error) => write!(f, "{}", error),
+        }
+    }
+}
+
 /// Given a consumer and producer, send a max payload size and commitment, and wait for the other side's corresponding `ReceivedPrelude`. Then send a `CommitmentReveal` message, before finally returning the received prelude.
 ///
 /// Attention: waiting for the other peer's prelude means that we delay sending our first messages, even though technically we would be allowed to do that. PRs welcome.

wgps/src/lib.rs

@@ -18,6 +18,7 @@ mod commitment_scheme;
 use commitment_scheme::execute_prelude::execute_prelude;
 pub use commitment_scheme::*;
 
+/// An error which can occur during a WGPS synchronisation session.
 pub enum WgpsError<E> {
     Prelude(ExecutePreludeError<E>),
 }
@@ -28,6 +29,14 @@ impl<E> From<ExecutePreludeError<E>> for WgpsError<E> {
     }
 }
 
+impl<E: core::fmt::Display> core::fmt::Display for WgpsError<E> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            WgpsError::Prelude(execute_prelude_error) => write!(f, "{}", execute_prelude_error),
+        }
+    }
+}
+
 pub struct SyncOptions<const CHALLENGE_LENGTH: usize> {
     max_payload_power: u8,
     challenge_nonce: [u8; CHALLENGE_LENGTH],