diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e6039a49..08fa600a8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,9 @@ The `Unreleased` section name is replaced by the expected version of next releas
### Added
### Changed
+
+- Replace `Stream.TransactAsyncEx` with `TransactEx`, providing an extended signature to expose the `ISyncContext` to `decide` as `master` [#263](https://github.com/jet/equinox/pull/263) [#272](https://github.com/jet/equinox/pull/272)
+
### Removed
### Fixed
diff --git a/src/Equinox/Equinox.fs b/src/Equinox/Equinox.fs
index 400e2a1a2..2e04b864c 100755
--- a/src/Equinox/Equinox.fs
+++ b/src/Equinox/Equinox.fs
@@ -23,33 +23,33 @@ type Stream<'event, 'state>
/// 1a. (if events yielded) Attempt to sync the yielded events events to the stream
/// 1b. Tries up to maxAttempts times in the case of a conflict, throwing MaxResyncsExhaustedException to signal failure.
member __.Transact(interpret : 'state -> 'event list) : Async =
- transact (fun state -> async { return (), interpret state }) (fun () _context -> ())
+ transact (fun context -> async { return (), interpret context.State }) (fun () _context -> ())
/// 0. Invoke the supplied decide function with the present state, holding the 'result
/// 1a. (if events yielded) Attempt to sync the yielded events events to the stream
/// 1b. Tries up to maxAttempts times in the case of a conflict, throwing MaxResyncsExhaustedException to signal failure.
/// 2. Yield result
member __.Transact(decide : 'state -> 'result * 'event list) : Async<'result> =
- transact (fun state -> async { return decide state }) (fun result _context -> result)
+ transact (fun context -> async { return decide context.State }) (fun result _context -> result)
/// 0. Invoke the supplied _Async_ decide function with the present state, holding the 'result
/// 1a. (if events yielded) Attempt to sync the yielded events events to the stream
/// 1b. Tries up to maxAttempts times in the case of a conflict, throwing MaxResyncsExhaustedException to signal failure.
/// 2. Yield result
member __.TransactAsync(decide : 'state -> Async<'result * 'event list>) : Async<'result> =
- transact decide (fun result _context -> result)
+ transact (fun context -> decide context.State) (fun result _context -> result)
- /// 0. Invoke the supplied _Async_ decide function with the present state, holding the 'result
+ /// 0. Invoke the supplied _Async_ decide function with the present state (including extended context), holding the 'result
/// 1a. (if events yielded) Attempt to sync the yielded events events to the stream
/// 1b. Tries up to maxAttempts times in the case of a conflict, throwing MaxResyncsExhaustedException to signal failure.
/// 2. Uses mapResult to render the final outcome from the 'result and/or the final ISyncContext
/// 3. Yields the outcome
- member __.TransactAsyncEx(decide : 'state -> Async<'result * 'event list>, mapResult : 'result -> ISyncContext<'state> -> 'resultEx) : Async<'resultEx> =
+ member __.TransactEx(decide : ISyncContext<'state> -> Async<'result * 'event list>, mapResult : 'result -> ISyncContext<'state> -> 'view) : Async<'view> =
transact decide mapResult
/// Project from the folded 'state, without executing a decision flow as Transact does
member __.Query(projection : 'state -> 'view) : Async<'view> =
- Flow.query (stream, log, fun syncState -> projection (syncState :> ISyncContext<'state>).State)
+ Flow.query (stream, log, fun context -> projection (context :> ISyncContext<'state>).State)
/// Project from the stream's 'state (including extended context), without executing a decision flow as Transact does
member __.QueryEx(projection : ISyncContext<'state> -> 'view) : Async<'view> =
diff --git a/src/Equinox/Flow.fs b/src/Equinox/Flow.fs
index 93bc1af0c..df774ab87 100755
--- a/src/Equinox/Flow.fs
+++ b/src/Equinox/Flow.fs
@@ -43,7 +43,7 @@ type ISyncContext<'state> =
module internal Flow =
/// Represents stream and folding state between the load and run/render phases
- type SyncState<'event, 'state>
+ type SyncContext<'event, 'state>
( originState : StreamToken * 'state,
trySync : ILogger * StreamToken * 'state * 'event list -> Async>) =
let mutable tokenAndState = originState
@@ -77,45 +77,45 @@ module internal Flow =
/// 2b. if saved without conflict, exit with updated state
/// 2b. if conflicting changes, retry by recommencing at step 1 with the updated state
let run (log : ILogger) (maxSyncAttempts : int, resyncRetryPolicy, createMaxAttemptsExhaustedException)
- (syncState : SyncState<'event, 'state>)
- (decide : 'state -> Async<'result * 'event list>)
- (mapResult : 'result -> SyncState<'event, 'state> -> 'resultEx)
- : Async<'resultEx> =
+ (context : SyncContext<'event, 'state>)
+ (decide : ISyncContext<'state> -> Async<'result * 'event list>)
+ (mapResult : 'result -> SyncContext<'event, 'state> -> 'view)
+ : Async<'view> =
if maxSyncAttempts < 1 then raise <| System.ArgumentOutOfRangeException("maxSyncAttempts", maxSyncAttempts, "should be >= 1")
/// Run a decision cycle - decide what events should be appended given the presented state
- let rec loop attempt : Async<'resultEx> = async {
+ let rec loop attempt : Async<'view> = async {
let log = if attempt = 1 then log else log.ForContext("syncAttempt", attempt)
- let! result, events = decide (syncState :> ISyncContext<'state>).State
+ let! result, events = decide (context :> ISyncContext<'state>)
if List.isEmpty events then
log.Debug "No events generated"
- return mapResult result syncState
+ return mapResult result context
elif attempt = maxSyncAttempts then
// Special case: on final attempt, we won't be `resync`ing; we're giving up
- let! committed = syncState.TryWithoutResync(log, events)
+ let! committed = context.TryWithoutResync(log, events)
if not committed then
log.Debug "Max Sync Attempts exceeded"
return raise (createMaxAttemptsExhaustedException attempt)
else
- return mapResult result syncState
+ return mapResult result context
else
- let! committed = syncState.TryOrResync(resyncRetryPolicy, attempt, log, events)
+ let! committed = context.TryOrResync(resyncRetryPolicy, attempt, log, events)
if not committed then
log.Debug "Resyncing and retrying"
return! loop (attempt + 1)
else
- return mapResult result syncState }
+ return mapResult result context }
/// Commence, processing based on the incoming state
loop 1
let transact (maxAttempts, resyncRetryPolicy, createMaxAttemptsExhaustedException) (stream : IStream<_, _>, log) decide mapResult : Async<'result> = async {
let! streamState = stream.Load log
- let syncState = SyncState(streamState, stream.TrySync)
+ let syncState = SyncContext(streamState, stream.TrySync)
return! run log (maxAttempts, resyncRetryPolicy, createMaxAttemptsExhaustedException) syncState decide mapResult }
- let query (stream : IStream<'event, 'state>, log : ILogger, project: SyncState<'event, 'state> -> 'result) : Async<'result> = async {
+ let query (stream : IStream<'event, 'state>, log : ILogger, project: SyncContext<'event, 'state> -> 'result) : Async<'result> = async {
let! streamState = stream.Load log
- let syncState = SyncState(streamState, stream.TrySync)
+ let syncState = SyncContext(streamState, stream.TrySync)
return project syncState }