Group (code,data,log) return values into types.Result

types/application.go

@@ -10,16 +10,16 @@ type Application interface {
 	SetOption(key string, value string) (log string)
 
 	// Append a tx
-	AppendTx(tx []byte) (code CodeType, result []byte, log string)
+	AppendTx(tx []byte) Result
 
 	// Validate a tx for the mempool
-	CheckTx(tx []byte) (code CodeType, result []byte, log string)
+	CheckTx(tx []byte) Result
 
 	// Return the application Merkle root hash
 	Commit() (hash []byte, log string)
 
 	// Query for state
-	Query(query []byte) (code CodeType, result []byte, log string)
+	Query(query []byte) Result
 }
 
 // Some applications can choose to implement BlockchainAware

types/result.go

@@ -0,0 +1,37 @@
+package types
+
+import (
+	"fmt"
+)
+
+type Result struct {
+	Code CodeType
+	Data []byte
+	Log  string // Can be non-deterministic
+}
+
+func NewResult(code CodeType, data []byte, log string) Result {
+	return Result{
+		Code: code,
+		Data: data,
+		Log:  log,
+	}
+}
+
+func (res Result) IsOK() bool {
+	return res.Code == CodeType_OK
+}
+
+func (res Result) Error() string {
+	return fmt.Sprintf("TMSP error code:%v, data:%X, log:%v", res.Code, res.Data, res.Log)
+}
+
+//----------------------------------------
+
+func NewResultOK(data []byte, log string) Result {
+	return Result{
+		Code: CodeType_OK,
+		Data: data,
+		Log:  log,
+	}
+}