Merge branch 'master' into var-conds

* master:
  Add Tx.Return and a return value from Atomically
  Panic when trying to set a nil Var

# Conflicts:
#	funcs.go

1 files changed, 22 insertions, 4 deletions

diff --git a/funcs.go b/funcs.go
index 7b5df38..4967e83 100644
--- a/funcs.go
+++ b/funcs.go
@@ -1,7 +1,7 @@
 package stm
 
 // Atomically executes the atomic function fn.
-func Atomically(fn func(*Tx)) {
+func Atomically(fn func(*Tx)) interface{} {
 retry:
 	// run the transaction
 	tx := &Tx{
@@ -9,9 +9,26 @@ retry:
 		writes: make(map[*Var]interface{}),
 	}
 	tx.cond.L = &globalLock
-	if catchRetry(fn, tx) {
-		// wait for one of the variables we read to change before retrying
-		tx.wait()
+	var ret interface{}
+	if func() (retry bool) {
+		defer func() {
+			r := recover()
+			if r == nil {
+				return
+			}
+			if _ret, ok := r.(_return); ok {
+				ret = _ret.value
+			} else if r == Retry {
+				// wait for one of the variables we read to change before retrying
+				tx.wait()
+				retry = true
+			} else {
+				panic(r)
+			}
+		}()
+		fn(tx)
+		return false
+	}() {
 		goto retry
 	}
 	// verify the read log
@@ -23,6 +40,7 @@ retry:
 	// commit the write log and broadcast that variables have changed
 	tx.commit()
 	globalLock.Unlock()
+	return ret
 }
 
 // AtomicGet is a helper function that atomically reads a value.